An Exclusive Interview with Gem Cutter John Dyer

Belinda Morris talks to renowned and much-admired lapidary John Dyer, one of the speakers at the 2016 Gem-A Conference, about the science and art of gem cutting. 

Did you train as a gemmologist or gem cutter?

I loved gems and business from an early age. I was also home-schooled and one of my parents’ strategies for teaching me was to purchase books on subjects I was interested in, so they bought books on gems and gemmology for me (Gem Identification Made Easy by Antoinette Matlins and Antonio C. Bonanno was one of the first) and that stoked my interest.

At 16 I wanted to start in the gem business and my dad said he would help me out. One thing led to another and we ended up going to Zambia to buy gemstones. We bought rough gems instead of cut ones to get a better deal and when we brought them back we took them to a cutter to have them cut. He did a really bad job on them and charged us a lot of money for it. 

This resulted in us getting mad and buying a faceting machine because, as my father said: “We can do that well, or better, ourselves, and cheaper too!” This all turned out to be a blessing in disguise because it helped us to discover that I love to cut gems. So although the gems we bought on that trip were not super profitable in the end, it started us in the direction of what has now become the focus of our business - high quality and creative gem-cutting. 

I never had any formal training. There were no lapidaries interested in teaching near me that I knew of, and as far as gemmology goes I mainly learned from books and practical experience. I would consider myself a far better cutter than gemmologist, but I do have certain practical, applicable gemmological techniques which help me when purchasing rough. Rough is almost easier to ID than cut gems, because you often still have the crystal habit, visible cleavage planes and more inclusions and other factors to help identify a gem and potential treatments it may have undergone. 

A 28.03 ct Citrine DreamscapeTM. Photo by John Dyer.
A 28.03 ct Citrine DreamscapeTM. Photo by John Dyer

Does the stone influence your design or do you choose the stone based on a particular cutting style that you want to see? 

The shape, colour and clarity of the rough are the main considerations in choosing the cut I am going to do. Usually I buy the best rough I can find and then cut to what I feel is best suited to it. There are times when I don’t buy a piece because I feel the shape and size it could cut would not have good marketable appeal, but other than that I pretty much let the rough dictate to me what it wants to be (that’s within certain limitations of marketability and visual appeal, of course). 

That challenge that each gem represents - trying to bring out its maximum potential - is one of the things I most enjoy about cutting. There are so many considerations that go into it and for the most part all those decisions are made on the fly as I saw and preform (pre-shape) the gem for dopping and faceting or carving. 

What is your favourite stone to work with and do you have a preferred design for it? 

My favourite gem to work with is aquamarine since it comes in reasonably large and clean gems, is easy to polish and has great transparency so it is well suited to a wide variety of different cutting styles. Also, since it isn’t dark, it shows the cut well instead of hiding it like some extra dark gems do. 

A 13.07 ct Aquamarine StarBrite TM. Photo by Lydia Dyer.
A 13.07 ct Aquamarine StarBriteTM. Photo by Lydia Dyer

There are sometimes cutting styles I prefer for specific gems; those with high dispersion (e.g. zircon) do better with flat faceted cuts than with concave facets or carving, since those tend to reduce the dispersion. Other gems with low dispersion I love to cut with concave facets or carving styles since they can increase the brilliance. It’s all part of the decision making process when deciding what to cut a specific piece or rough into. 

A 46.81 ct Aquamarine Super Trillion TM. Photo by John Dyer.
A 46.81 ct Aquamarine Super TrillionTM. Photo by John Dyer

You use many less well-known gemstones, do you find that this increases the public’s awareness of these stones, highlighting how beautiful they can be?

As far as using ‘less well-known’ gems go I find that the market is much more accepting of a wide range of gems than in the past. TV shopping has introduced many strange gem types to a large public audience and a certain percentage of that public has gone on to learn a lot about gems and become educated and sophisticated buyers. This, coupled with how expensive the ‘traditional’ gems have become, has really opened a wide door to the lesser known gems. 

That being said though, most of the gems I cut are still within the parameters of what is familiar to most jewellers - aquamarine, beryl, morganite, citrine, amethyst, ametrine, garnet of all kinds, sapphires, emerald, ruby, peridot, tourmaline (all colours), spinel and zircon make up most of my inventory.

Morganite StarBriteTM 50.92 ct cut by John Dyer & Co. Photo by Lydia Dyer.
Morganite StarBriteTM 50.92 ct cut by John Dyer & Co. Photo by Lydia Dyer

Sometimes I will do a very rare gem, such as bicolour spessartite, phenakite, oligoclase or similar, but they are the exception rather than the rule.

What do you endeavour to reveal in stones? 

Essentially what I am looking to reveal is the full potential for beauty that is in each piece of rough. So much labour goes into the searching for and mining of gem rough that I feel it should be cut in a manner that respects its true rarity and uniqueness. But at the same time some sacrifices of size and weight will need to be made for the gem to achieve its maximum beauty. That is the goal that I aim for. 

What do you look for when selecting a piece of rough? 

When selecting rough I look at the size, shape and clarity of each piece. I also take into account the value of the finished piece because there is a lot of labour involved in our cutting and if the finished value of the gem is too low we will not recoup our labour costs. For that reason there are some pieces of rough that are cool and pretty but I just can’t buy them because they won’t generate a profit. 

Do you travel to mines around the world to procure your own rough or do you often buy at shows? 

I have travelled to various countries in search of gems. My most valuable gem (my wife) is Brazilian from the state of Paraíba so the search has paid off! However, gems are often found in very small quantities and a trip direct to the mines can be a fruitless affair since there might not be any production for months at a time. This often results in my needing to buy from middlemen of some kind. Over the years we have formed relationships with a number of rough suppliers who bring us a variety of rough, that it would have been very hard to have access to on our own. After all, cutting is a time consuming business and if I spent all my time running about after rough I wouldn’t get much cutting done. 

Have you had any major cutting catastrophes? 

Major cutting catastrophes are something you like to put out of your mind, but there have been a number of them over the years. There was the kilo of pink tourmaline rough we heated without grinding clean first and broke almost all of it. There was a bixbite (red beryl) from Utah that cost us thousands of that we hoped to get over a carat’s worth of finished cut stone out of it, but it shattered due to internal stress and we ended up with three very small gems from it. There was the imperial topaz that I was carving and got too hot and broke it in half… and many other gems that have broken during carving, or been chipped or something similar. Over 20 plus years of cutting there are a lot of things like that which happen.

Talk us through the process of one of your famous cuts such as the Super Trillion™. What’s the process of cutting a gem in this way? How long does it take to cut some of your most famous designs?? 

The Super Trillion™ is all flat faceted and is an adaptation of a cut that was explained to me by Chris Remen (now deceased) which over time I tweaked to make a number of improvements to. The result is a semi-traditional looking trillion which I feel is super. Since it has so many facets it is very time-consuming to cut. How long it takes depends completely on the type of material and the size of the gem but it usually takes a day or longer to complete. 


A 26.11 ct Citrine Super TrillionTM. Photo by John Dyer.A 26.11 ct Citrine Super TrillionTM. Photo by John Dyer

Do you have any advice for people who want to take up lapidary? 

To take up lapidary as a hobby, the best thing to do is search for a local lapidary club. Often there will be retired members who will teach cutting for a very reasonable price and this often allows you to avoid the initial relatively high cost of the machinery and supplies. For those who want to make this a profession, I would recommend studying the market to be sure that it is really what they want to do… because it is not the easiest thing to make money at. 

You need to be a skilled cutter (something that often takes five years or more to accomplish) and make large investments in raw materials if you are going to sell your own gems. If you don’t sell your own gems, you are going to need to find a niche market for your cutting services and be very fast if you expect to make money because much of the gem trade is used to Asian pricing on gem cutting and that is hard to compete against until you educate your clientele about the difference in look and quality. That means a lot of outreach and marketing is involved. 

Rare red beryl (bixbite), cut by John Dyer & Co. Photo by Lydia Dyer.
Rare red beryl (bixbite), cut by John Dyer & Co. Photo by Lydia Dyer

You’ve won many awards for your work; which means the most to you? 

The award that means the most to me is the first place I took recently at the German Award for Jewellery and Precious Stones Idar-Oberstein 2015. This is one of my favourite competitions, but the fact that you have to adhere to a theme makes it more complicated. You might have a perfectly beautiful idea for a gemstone cut, but it must go with the theme to win. The theme in 2015 was ‘Light My Fire’, so I thought that an orange gem would fit well with the idea of fire. With this in mind, I searched through my stock of rough and selected a deep orange citrine, which, once ground clean, was a flame shape. Despite this it was still a challenge to decide what to do with the underside of the gem to make it look like fire. However, an idea came to me to execute a pattern that I had never done or seen before and which required an adaptation of my existing machinery and techniques - the result is a gem with a flame shape, but which also has little flame-shaped internal facets on the back which reflect light individually with varying intensities so that they look like flames shooting upwards as the gem is moved. 

John Dyer's flame-cut citrine, first place winner in the 2015 German Award for Jewellery and Precious Stones in Idar-Oberstein. Photo by Lichtblick Foto-Design, Hiltrud & Jurgen Cullmann of Schwollen, Germany.
John Dyer's flame-cut citrine, first place winner in the 2015 German Award for Jewellery and Precious
Stones in Idar-Oberstein. Photo by Lichtblick Foto-Design, Hiltrud & Jurgen Cullmann of Schwollen, Germany

Where do you see yourself going with your talent? What’s next for you in the lapidary world? 

It might not be super romantic, but I guess what I see is gradually improving what I already do and adding new styles and techniques to that. As a result of this I feel that each year our gems are better cut, more beautiful and more saleable. ■   

To view John Dyer's work click here

This article originally appeared in Gems&Jewellery Sept/Oct 2016 / Volume 25 / No. 5 pp. 28-32

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.


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Getting to Grips with GemTOF Technology

This article by Guy Lalous ACAM EG digests a technical article from The Journal of Gemmology and discusses the capabilities of Laser Ablation Inductively Coupled Plasma Time-of-Flight Mass Spectrometry (LA-ICP-TOF-MS) compared to conventional Inductively Coupled Plasma Quadrupole Mass Spectrometry (ICP-Q-MS). Potential applications of this new analytical technique are also described.  

Gem testing has evolved into an advanced materials science using sophisticated instrumental technologies for detailed chemical and structural analyses. The chemical analysis of gem materials allows identification of synthetics and treatments. Trace-element analysis is useful to identify the geographical origin of high-end stones. When the origin of a stone has a significant impact on it’s value, the cost associated with this technique may be  justified.

Six Blue Sapphires Medium Sized Image
Six blue sapphires (various client stones weighing approximately 2–36 ct) are shown on an historical map of the famous gem locality of Mogok, Myanmar. Quantitative chemical data can be helpful for determining the geographic origin of sapphires. Map from Gordon (1888); photo by L. E. Cartier and Julien Xaysongkham, SSEF.

How does LA-ICP-MS work?

 The LA-ICP-MS analysis process can be thought of in two main parts: material sampling i.e. Laser Ablation (LA) and chemical analysis i.e. Inductively Coupled Plasma Mass Spectrometry (ICP-MS). A tiny, nearly invisible ablation pit is caused by the laser, into the girdle of the gemstone. There will be minimal damage as the laser vaporises only a microscopic amount of the sample for analysis. It nebulizes the material and the aerosol produced is transferred in a gas stream to an ICP-MS for elemental and/or isotopic analysis. An ICP-MS combines a high-temperature Inductively Coupled Plasma (ICP) with a Mass Spectrometer (MS).   The ICP is an ionisation source where the energy is supplied by electric currents, which ionises the atoms. These ions are then separated based on their mass-to-charge ratio (m/Q) and detected by the MS.  

What is LA-ICP-MS used for?

LA-ICP-MS is recognised as one of the most important spectrometric techniques and has been used in gemmology for quantitative chemical analysis. It provides data that can be used to create chemical fingerprint diagrams for geographical origin determination.

What is ICP-Q-MS?

There are multiple varieties of ICP-MS instruments, which use different mass-separation schemes in analysis. Of these the ICP-Q-MS, which uses a quadrupole is the most popular. The quadrupole is a mass filter. The quadrupole consists of four cylindrical rods arranged so that the ionised sample travels down the centre. Depending on the electro-magnetic field of the rods, the trajectory of the ionised particles is affected, with selected ionic weights based on the m/Q being filtered out and the ions of interest reaching the MS detector. The ability to filter ions on their m/Q allows ICP-MS to supply isotopic information. Different isotopes of the same element have different masses.

What are the limitations of ICP-Q-MS?

The user of this technique has to define a preselected list of isotopes. Isotopes are sequentially measured one at a time, the ‘limited’ sample volume is divided (segmented) between all measured isotopes, thereby drastically reducing the effective sensitivity if many isotopes are monitored.

What are the capabilities of ICP-TOF-MS?

ICP-TOF-MS is one of the latest and most advanced technologies in the ICP-MS family. Time-Of-Flight (TOF) uses the principle that the ‘flight’ duration for one ion passing through a fixed flight tube is related to its m/Q.  Lighter ions take less time to travel the same distance compared to their heavier counterparts with the same charge, provided they have identical kinetic energy, therefore achieving mass separation. ICP-TOF-MS acquires spectra from the lightest to the heaviest isotopes at a higher speed as well as achieving a better resolving power than conventional Q-MS. It ‘snaps pictures’ of the full and continuous mass spectrum without the need to assign isotopes of interest. Such a spectrum reveals almost the full elemental composition, reaping the benefits of the robust plasma source and there is no need to re-ablate the stone due to an incomplete or ‘badly’ chosen predefined list of isotopes.

What practicalities are there to consider with ICP-TOF-MS?

Due to technical limitations the ICP-TOF-MS model described in this article cannot measure light isotopes while maintaining a high sensitivity for heavy isotopes. It takes two measurements to complete the full elemental analysis from Lithium to Uranium. Limit of detection (LOD) values range from single-digit parts per billion (ppb) for heavy elements to low parts per million (ppm) for light elements. TOF-MS provides better LOD than Q-MS. TOF-MS collects all information in the full mass spectrum with no information loss.

Figure 2 Journal Digest LA-ICP-TOF-MS
(a) An averaged full elemental mass spectrum is shown from a LA-ICP-TOF-MS measurement of NIST610, a silicate standard reference material. Mass-to-charge ratios through the entire elemental range were acquired simultaneously. (b) Details of the orange region in (a) illustrate the mass resolving power of of TOF-MS (m/Δm ≈ 3,000), which is better than quadrupole MS (normally m/Δm≈ 300) in resolving some interferences.

What are the potential applications?

The possibilities of the technique will enhance applications such as trace-element characterisation of gemstones and pearls for origin determination and treatment detection, and will open new research opportunities for age dating, inclusion studies and high-spatial-resolution chemical mapping of gems.

The new instrument is called GemTOF and was installed at SSEF in July 2016. ■  

To find out more information about this exciting technique visit GemTOF

This is a summary of an article that originally appeared in The Journal of Gemmology entitled ‘Simultaneous High Sensitivity Trace-Element and Isotopic Analysis of Gemstones Using Laser Ablation Inductively Coupled Plasma Time-of-Flight Mass Spectrometry’ by Hao A.O. Wang, Michael S. Krzemnicki, Jean-Pierre Chalain, Pierre Lefèvre, Wei Zhou and Laurent E. Cartier 2016 / Volume 35 / No. 3 pp. 212-222

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.


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Harrods Unearths 228.31 ct Diamond from its Vaults for Private Sale

London department store Harrods has delved into its vault to unveil a 228.31 ct diamond for the first time.

Nicknamed ‘The Harrods Diamond’ by its anonymous owner, the stone has been released from the retailer’s safety deposit vault and is now available to view by appointment only.

The pear-shaped, G-colour, VS1-clarity polished diamond can be counted among the world’s rarest, largely due to its incredible size but also its exceptional cut and symmetry.

While the majority of large diamonds are sold at auction, Harrods is offering interested parties the chance to buy this diamond privately on a first come, first serve basis.

Read more: The History of Diamonds in Engagement Rings

Chief merchant at Harrods, Helen David, comments: “We are thrilled to unveil one of the world’s rarest diamonds, the so-called Harrods Diamond, named after the iconic Knightsbridge store.  It is rare that stones of this weight, cut, polish and symmetry are sold outside auction, so this is an exceptional opportunity for Harrods’ customers and a very exciting moment in Harrods’ history.”

228.31 ct Harrods' Diamond
The 228.31 ct Harrods Diamond. Image courtesy of Harrods

Harrods has long offered its most affluent customers access to its Victorian-era safe deposit facilities, comprising small boxes all the way up to whole strong rooms. All are available for fixed annual rates and are accessible via a single key, which remains in the customer’s possession at all times.

Although the price of the Harrods Diamond is only available upon application, predictions have been made as to the final figure.

In 2013, Christie’s auctioned one of the world’s most exceptional pear-shaped diamonds – an internally flawless, 101.73 ct, D-colour gem with perfect symmetry. It was eventually purchased for $26,746,541 (£21.5m).

Although the Harrods Diamond differs in colour, its larger size and luxurious association is likely to see its price soar to more than £20 million. ■  

Interested in finding out more about diamonds? Sign-up to one of Gem-A's diamond courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover image courtesy of Harrods.


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Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

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Understanding Spinel: The Alternative August Birthstone

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The French Gem Connection

Gem-A Accredited Teaching Centre (ATC) the Laboratoire de Gemmologie de Marseille (LGM) recently held its 5th Annual Gemmologist Conference. Katherine Palthey FGA, one of the speakers at the event summarises the day. 

On Sunday 11 December LGM held their Conference at the Mercure Hotel in Marseille France. The Director Agata Cristol FGA DGA organised a successful Conference with guests such as Thierry Pradat FGA of Gems-Plus and guest speakers Alexandre Eichler FGA, Katherine Palthey FGA, Laurent Seneca FGA and Bruno Cupillard FGA.

The topics discussed during the Conference were centered on gem treatments and their impact on retail prices. Alexandre Eichler FGA, Director of Gems River, specialises in sapphires and has spent months in numerous sapphire mines this year confronted with both ‘old burn’ (traditional heating) and ‘new burn’ (heating with diffusion) treatments. He pointed out in detail the differences between the methods and the impact they have on today’s market prices. 

Natural unheated sapphires, LGM blogpost
A rare pair of 6.01 ct natural unheated sapphires from Bo Phloi. Photo credit Alexandre Eichler, Gems River

Katherine Palthey FGA, Gem Expert Consulting, presented Burmese lavender jadeite and the origins of its colour, which is manganese. Burmese lavender jadeite shows an absorption band at 437 nm and a large absorption near 580 nm for manganese. Colour treated jade and imitations have a different spectrum, demonstrating they are not Burmese lavender jadeite. After an intricate explanation on differentiating natural jade from treated jade (shown in the figure below) she announced her research results on over 50 jadeite pieces and shared her inside secrets on how to identify high quality jadeite.

Burmese lavender jadeite options A,B, and C in LGM blogpost
L-R: Burmese natural lavender jade, colour treated jade and an impressive imitation made of Calcite. Photo credit Katherine Palthey FGA, Gem Expert Consulting

Laurent Seneca FGA lives between Colombia and Monaco and dedicates his time to fine quality Colombian emeralds. Laurent explains how the past 20 years have seen an enormous increase in the use of synthetic epoxy resins to enhance emerald’s clarity. He has seen an alarming rise in polymer resins such as Gematrat and Permasafe, being used on Colombian emeralds and he explained the long term implications of these treatments. In the Bogota market alone, he estimates up to 95% of the emeralds today are being treated with hardened epoxy resins.

Colombian emerald, LGM blogpost
1.4 ct natural emerald from Muzo, Colombia. Photo credit Laurent Seneca FGA

Demonstration stations with microscopes between lectures were busy as guests rushed to see the latest in sapphire, jadeite and emerald treatments being introduced to the market this year. There was so much interest, Agata extended the day by an extra hour for our guests.

Guest of Honor, Bruno Cupillard FGA from Aventures Cristallines rounded up the day’s talks. Bruno is a successful mineral and gemstone photographer known for his unique and emotionally triggering views inside gemstones. The audience was taken behind his camera to see his secret photographic techniques, and he generously shared his tips on diffused lighting, background settings and more. He shared a breathtaking video on his photos of scenes and nature’s beauty presented in inclusions such as Paesine – a limestone that has split and shifted to create a scenic landscape…we were all mesmerized. 

Hotel Mercure served us their lovely French cuisine and after digesting our expressos, we jumped in to the Annual Gemmology Tournament. Organised by Thierry Pradat FGA of Gems-Plus, we were each passed 40 different gemstones and with one minute and just the loupe, we had to identify with precision all the material. The ambiance was relaxed and laughter bounced off the walls, although all eyes were on their loupes. Thierry Pradat FGA is one of France’s largest gemstone dealers and his business Gem-Plus is a true reference point for professional jewellers, designers and avid collectors. Thierry generously offered an amazing rhodolite garnet for the winner who was none other than our guest speaker Bruno Cupillard.

Thierry Pradat LGM blogpost
Thierry Pradat introducing the Annual Gemmology Tournament

Agata Cristol FGA DGA, took another minute at the close of the Conference, while waving the Gem Guide, to remind all of us to be cautious when classifying treatments on certificates and disclosing them to customers. The overall aim of the discussion was seeking international agreements on classifying treatments within these materials and to improve our commitment to ethical mining issues such as dynamiting the beautiful mountains in Colombia. A wonderful experience and I look forward to Conferences such as these in the future. ■  

Interested in finding out more about diamonds? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover image 2016 Conference Speakers and Cecile Agu FGA. L-R: Alexandre Eichler FGA, Cecile Agu FGA, Katherine Palthey FGA, Bruno Cupillard FGA, Thierry Pradat FGA and Agata Cristol FGA DGA.


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

Read more


Birthstone Guide: Sapphire for Those Born in September

Birthstone Guide: Sapphire for Those Born in September

Legend describes sapphire as a stone of honesty, trust and prosperity, bringing inner peace and protection to its wearer. Here, we consider the many facets of the September birthstone...

Read more


A First Time Visit to Intenational Jewellery London 2019

A First Time Visit to Intenational Jewellery London 2019

Gem-A’s communications assistant, Olivia Gillespie, reflects on her first experience at one of the UK’s biggest jewellery trade shows, International Jewellery London.

Read more


Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


Buying Guide: Which Gemstones are in the Beryl Family?

Buying Guide: Which Gemstones are in the Beryl Family?

Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

Understanding Red Beryl

Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

Look at any list of the top 10 most famous gemstones in the world and you will undoubtedly come across the Star of India. Here, we find out more about this incredible star sapphire and discover its fantastical history, which reads like the plot of a Hollywood movie.

Read more


The Gems&Jewellery Autumn 2019 Issue Has Landed!

The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

Read more


Birthstone Guide: Peridot for Those Born in August

Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

Read more


Additional Info

Read more...

Gem Central with Marcus McCallum FGA

Local gem-dealer Marcus McCallum FGA hosted this December’s Gem Central. Specialising in unusual and high quality stones, Marcus has spent forty years in the trade. Angharad Kolator Baldwin reports on the evening…

Marcus is based in Hatton Garden and has seen many changes in the trade in the last few decades. Attendees heard his take on trends in the industry, his personal views on gem testing and the challenges faced by gem dealers. Participants were lucky enough to look at stones from Marcus’ personal collection and view the fossils that kick-started his own love of mineralogy when he was just six years old.

Fossil Sea Urchin, from Marcus McCallum's personal collection, Gem Central Blogpost
Fossil Sea Urchin, from the personal collection of Marcus McCallum FGA

The Bruton room at Gem-A headquarters was packed with people who came to find out more from long standing member and supporter Marcus McCallum FGA. This Gem Central was the last Gem-A event of 2016 and it provided an excellent opportunity for gemmology enthusiasts to gather together, covet beautiful gemstones and enjoy a drink and a mince pie.

Marcus McCallum showing his personal collection at Gem Central
Marcus McCallum FGA and Gem Central attendees

So what has changed in the gem industry over the past 40 years? Marcus described how there used to be more small business in the trade, looking for unusual stones. He talked about the branding on stones and the concept of ‘best’ that is now so heavily sought after. This does not sit well with Marcus who believes it is the beauty of the gem that should be emphasised, whether it is pigeon blood in colour or not, beauty is the most important. 

Rutilated quartz; Marcus McCallum's personal collection, gem central blogpost
Rutile and haematite in quartz, from the personal collection of Marcus McCallum FGA

Historically buyers were not as interested in the origin of stones and the premiums seen today for Burmese rubies and Kashmir sapphires simply did not exist. He also remarked that dealers did not previously distinguish between heat treated and non-heat treated stones, in fact sapphires were routinely treated. The current trend in paying a higher price for non-heat treated stones is a good move in Marcus’ opinion. He does believe that you should pay a premium for untreated stones, but raised the question, does the origin truly matter?

Pinpointing the origin of a stone is a great challenge for gemstone dealers. Laboratory testing costs a great deal of money and this is not always paid off by the result. Marcus gave examples where multiple labs do not always return the same result for the same stone. He described how incredibly difficult it is to definitively locate the origin of a stone, partly due to the fact that the same mine can support very different mineralogical characteristics. 

Marcus called himself a romantic, preferring artisanal mining, where the revenue generated through the mine can trickle back down to the local community. He has travelled widely visiting different mines and finding some remarkable stones. He also believes it is down to the trade to look at how stones are marketed, how different localities are perceived by the commercial market and consumer, and to encourage the beauty of a stone to shine brighter than its locality. Gemmologists shouldn’t be afraid to rely on their own knowledge he said and challenge a gemstone certificate if necessary. 

Barbara Kolator looking through a loop at Gem Central with Marcus McCallum
Barbara Kolator FGA DGA looking through her loupe

Consumers are moving away from diamond engagement rings and Marcus said that colour is coming back. This is the opportunity for jewellers to educate consumers and weave a story around coloured stones. 

Gem Central, which is held once a month at Gem-A headquarters is a fantastic time for gemmology students and gem enthusiasts to have more practical opportunities and socialise with other individuals with the same interests. The events are hosted by a variety of speakers and no two evenings are ever the same. ■

Interested in attending a Gem Central event? For more information about our upcoming Gem Central events visit the Gem Central page or email events@gem-a.com.

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

Cover image goethite in ametrine, from the personal collection of Marcus McCallum FGA.


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

Read more


Birthstone Guide: Sapphire for Those Born in September

Birthstone Guide: Sapphire for Those Born in September

Legend describes sapphire as a stone of honesty, trust and prosperity, bringing inner peace and protection to its wearer. Here, we consider the many facets of the September birthstone...

Read more


A First Time Visit to Intenational Jewellery London 2019

A First Time Visit to Intenational Jewellery London 2019

Gem-A’s communications assistant, Olivia Gillespie, reflects on her first experience at one of the UK’s biggest jewellery trade shows, International Jewellery London.

Read more


Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


Buying Guide: Which Gemstones are in the Beryl Family?

Buying Guide: Which Gemstones are in the Beryl Family?

Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

Understanding Red Beryl

Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

Look at any list of the top 10 most famous gemstones in the world and you will undoubtedly come across the Star of India. Here, we find out more about this incredible star sapphire and discover its fantastical history, which reads like the plot of a Hollywood movie.

Read more


The Gems&Jewellery Autumn 2019 Issue Has Landed!

The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

Read more


Birthstone Guide: Peridot for Those Born in August

Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

Read more


Additional Info

Read more...

Inside the World of Photomicrographer Danny Sanchez

Award-winning photographer Danny Sanchez GG, a speaker at the 2016 Gem-A Conference, reveals the secrets of photomicrography, the equipment he swears by and his favourite gemstones to photograph.

Q. What drew you towards photomicrography?

I was a working musician in Los Angeles and wanted a change of pace. I’d always loved gems and minerals and when I discovered that you could study them, their origins and applications, at the Gemological Institute of America, I couldn’t enrol quickly enough. The day I opened the course material and saw an inclusion photomicrograph, I was hooked.  

Q. What special equipment do you use?

I might be a little biased so I feel like a lot of my equipment is special. I think my most unusual piece of equipment is a vertical stepping rig that moves the microscope mere microns at a time.  

The home 'laboratory'
Danny Sanchez' home 'laboratory'

Q. Can you explain stacking for those that don’t know?

Microscopy deals in very narrow focal planes. A single photo has very little that is actually ‘in focus’. Focus stacking is a technique that allows one to merge multiple photos, each with different focal planes, into a single photo with greater depth of field. This is stacking. Using this technique, one is able to ‘manufacture’ depth. There is definitely a way to overuse stacking. Besides the visual residue that can be found in some photo ‘stacks’ (a group of photos merged into one), if a photo is rendered with too much depth, the viewer can lose perspective. Simply put, but somewhat counterintuitively, a photo with too much depth can look flat. 

A single photomicrograph play of colour in opal from Jalisco, Mexico. Field of view 3.05 mmThe complete stack of 81 photos. Field of view 3.05 mm

Left: A single photomicrograph play of colour in opal from Jalisco, Mexico. Field of view 3.05 mm. Right: The complete stack of 81 photos. Field of view 3.05 mm

Q. Do you look at images from earlier and wish you could retake some of the spectacular ones to add the ‘dimension’ it offers?

I definitely understand the impulse to go back and re-do a shot, but it’s not a strong one for me. I’m always trying to look forward, and to reproduce or re-tool an image I’ve already made seems like a step backward — particularly in light of how many dynamic subjects this industry offers. (For more information on stacking see Prince, N., ‘Use of Stacking Software for Expanding Depth-of-Field in Inclusion Photomicrography’, The Journal of Gemmology, 2014, 34(3), 188–89).  

Q. Do you have any advice for gemmologists wishing to try photomicrography at home?  

There are an overwhelming number of details to consider when trying to take a successful photograph through the microscope, and it’s hard to see the forest for the trees. The simplest recommendation I can make is: buy more light than is necessary. Gemmologists are used to using a specific type and amount of light during observation and imagine that will be sufficient when they sit down to take a photograph. It never is. Light is everything in photography; it’s even more important in photomicrography.  

Q. Do you have any particular favourite inclusions or gemstones to photograph?  

This past year I’ve immersed myself in opal with matrix. I have yet to find a mineral more dynamic that so readily yields actual landscapes. Part of what I look for in my own work is the feeling of being transported somewhere ‘other’. I enjoy the challenge of finding that in quartz or corundum, but when I work with opal in matrix, it’s almost like the photo takes itself.   

Opal from Magdalena. Jalisco, Mexico. Field of view 3.05 mm.
Opal from Magdalena. Jalisco, Mexico. Field of view 3.05 mm

Q. How do the public react to your photos? 

Most (non-gemmological) people don’t know what they’re looking at when standing in front of my photos. Once I tell them that it’s a photo of the inside of a gemstone, more often than not, they don’t believe me. Finally, when they do, they have a million questions. It’s really great to see people so invigorated about gems and minerals. I’m sure they’re much more interested when they leave than before they arrived. 

Ilmenite and hematite in orthoclase feldspar from Harts Range, Australia. Field of view 3.05 mm.
Ilmenite and hematite in orthoclase feldspar from Harts Range, Australia. Field of view 3.05 mm

Q. How do you source the stones that you work with? 

Mostly, I’ll buy at trade shows, looking through dealers’ back stock inventory — stones that, for one reason or another, have been passed over. Part of the joy of my process is these little discoveries and bringing something out of them that no one could have imagined. There’s something about owning the stones I work with (and hopefully producing an image from them) that makes the final product that much more satisfying. I’m not sure I can satisfactorily articulate why. Maybe, like every other gemmologist, I just like to hoard stones. 

Q. Do you see your photos as an educational tool or as an art form? 

Art is an inherently selfish act and mine is certainly no exception. All I ever wanted was to capture in my images a sense of mystery and wonder. It is purely self-serving and in this regard, it’s very ‘artsy’. But when people look at my images and discover that they are photos of actual minerals inside other minerals, there is an immediate spark of curiosity. The moment that happens, my photos become educational. 

Q. How long does it take you to capture the ‘magic’ shot? 

I’ll sit down with a parcel of stones and spend hours turning them over in my hands, changing the lighting environment, trying my best to disappear into the process. Once I’ve decided on which stone I’ll pursue, it could take another hour or so to test shoot dozens of lighting environments. The shooting and processing of a stack of 100 or more photos takes another 30 to 40 minutes. The real work happens over the following several days while I digitally develop the photo, just as I would if I were working in a traditional darkroom. 

Metal sulphide in fluorite, from Elmwood, Tennessee. Field of view 1.8 mm.
Metal sulphide in fluorite, from Elmwood, Tennessee. Field of view 1.8 mm

Q. What’s the most frustrating thing about photomicrography? 

The most frustrating thing is that I can’t do it for a living. My photos don’t have to be perfect, but they have to be representative of the view through my oculars, at the same time capturing the feeling of the moment of discovery. If I don’t feel I’ve done that after I’ve gone through the process of taking the shot(s) and developing the stack, it can be very frustrating. 

Q. What are your future plans for your work? 

Most of my work for the past few years has focused on atmosphere, the space within the stone and not any particular inclusion or the capturing of inclusions. That’s what interests me the most and that’s what I see myself pursuing; capturing and creating the space within gems. 

Q. If fleeing a burning building, what equipment do you grab?

Luckily for me, I’m not a photographer in the traditional sense of the word. I didn’t grow up aspiring to take photos nor did my penchant for gadgetry lean in that direction. My entry into the world of ‘prosumer’ cameras and lenses began with photomicrography. Because of this, I don’t have a collection of lenses or cameras that would make it hard to choose if fleeing a burning building. My most crucial pieces of equipment fit into one small hard case. I’m definitely fortunate in that regard. 

Q. Your studio improvisations suggest you have a good eye for engineering solutions to suit your needs…

Everything I have done, I’ve done on the shoulders of others. Of course, I’d like to think of myself as a tinkerer and problem solver but most of my equipment has existed in some form, on someone else’s desk, in someone else’s setup. It wasn’t easy piecing it all together but with help from a very small handful of people from around the globe, I’ve put together something that I’m really proud of. 

Q. Another big part of the job these days is software; how do you select the software you use? 

I’ve mentioned the stacking software and while that’s a tricky nuanced piece of software, it performs one function and is therefore finite in its ability to affect a photograph. Beyond that there is developing software such as Lightroom and Photoshop. Together, they can be used to alter an image in infinite ways. While they are indispensable tools, I try to remain as faithful to the view through my oculars as possible. 

Q. What are the ‘frontiers’ to be explored in photomicrography? 

I think the frontiers of photomicrography lay in the direction of software. We’re so lucky to be living in a time of amazing advances, in what computers can do to aid in our perception of the world around us. One day I hope to be able to pop on a pair of VR glasses and take a flight through a Kashmir sapphire or Mexican opal. 

Q. Do you have any gemmological heroes? 

Of course, Eduard Gübelin and John Koivula. Without their work, who knows where I’d be. 

Q. Who first encouraged you to be a photographer? 

In 2007, a year or so after I bought my first microscope, I was working at a trade show and was introduced to Edward Boehm. I already knew who he was, both in the trade and his family’s importance in gemmology. I shook his hand and told him, with no small amount of youthful hubris, that I was going to be a photomicrographer. He flashed me that great smile and told me to go for it. Every subsequent time I ran into him, he would always ask how it was going and if I’d made any progress with my photos. I was the smallest blip in his periphery but for the next five years he never forgot to ask about my photos. During that time I struggled with the pursuit itself and a lot of self-doubt. It wasn’t until 2013 that I was proud enough of my work to share it with the general public. His polite consideration was such a small gesture but it made me think: if this great gemmologist, grandson of the man who helped pioneer this field, hasn’t forgotten about me and my pursuit, I can’t forget either. ■   

To view more of Danny Sanchez's work click here or visit his Instagram @mineralien

This article originally appeared in Gems&Jewellery May/June 2016 / Volume 25 / No. 3 pp. 10-12

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover image Opal, from Jalisco, Mexico. Field of view 3.05 mm. All images courtesy of Danny Sanchez. 


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

Read more


Birthstone Guide: Sapphire for Those Born in September

Birthstone Guide: Sapphire for Those Born in September

Legend describes sapphire as a stone of honesty, trust and prosperity, bringing inner peace and protection to its wearer. Here, we consider the many facets of the September birthstone...

Read more


A First Time Visit to Intenational Jewellery London 2019

A First Time Visit to Intenational Jewellery London 2019

Gem-A’s communications assistant, Olivia Gillespie, reflects on her first experience at one of the UK’s biggest jewellery trade shows, International Jewellery London.

Read more


Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


Buying Guide: Which Gemstones are in the Beryl Family?

Buying Guide: Which Gemstones are in the Beryl Family?

Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

Understanding Red Beryl

Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

Look at any list of the top 10 most famous gemstones in the world and you will undoubtedly come across the Star of India. Here, we find out more about this incredible star sapphire and discover its fantastical history, which reads like the plot of a Hollywood movie.

Read more


The Gems&Jewellery Autumn 2019 Issue Has Landed!

The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

Read more


Birthstone Guide: Peridot for Those Born in August

Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

Read more


Additional Info

Read more...

Last Chance to See the Record-Breaking Foxfire Diamond at the Smithsonian

The largest known uncut, gem-quality diamond mined in North America is available to view at the Smithsonian’s National Museum of Natural History until February 2017.

The Foxfire Diamond, which weighs more than 187 carats, was unearthed in August 2015 at the Diavik Diamond Mind in the Barren Lands of Canada’s Northwest Territories. The site is just 130 miles from the Arctic Circle, leading those who discovered the gem to name it ‘Foxfire’ – inspired by an aboriginal description of the Northern Lights as similar to the swish of fox tails.

The discovery of the Foxfire caused something of a stir among miners in the region, who believed such large, gem-quality diamonds were unlikely to exist in the area. In fact, diamonds found over the previous decade generally peaked at six carats. Because of this, the mine’s equipment was configured to sift out stones smaller than six carats, while pulverising larger ones.

Read more: Harrods Unearths 228.31 ct Diamond from its Vaults for Private Sale

The 187.63 ct Foxfire should have been crushed, but its uncommonly flattened shape enabled it to safely pass through the filters.

Diamond enthusiasts in North America, or indeed those travelling to Washington D.C., are encouraged to see the Foxfire before it is removed from public view on February 16 2017. It will also be displayed alongside the infamous Hope Diamond in the Harry Winston Gallery of the museum.

Read more: An Exclusive Interview with Gem Cutter John Dyer

In June 2016, the Foxfire Diamond was acquired in an international auction by Deepak Sheth of Amadena Investments LLC/Excellent Facets Inc. Sheth elected to preserve the diamond intact, maintaining both its unique characteristics and interesting origin story.

He says: "Having North America’s largest known uncut, gem-quality diamond on display at the Smithsonian is a testament to the rarity of the Foxfire diamond. It also represents another significant chapter in the diamond’s remarkable story." ■  

Interested in finding out more about diamonds? Sign-up to one of Gem-A's diamond courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover image courtesy of Amadena Investments LLC.


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

Read more


Birthstone Guide: Sapphire for Those Born in September

Birthstone Guide: Sapphire for Those Born in September

Legend describes sapphire as a stone of honesty, trust and prosperity, bringing inner peace and protection to its wearer. Here, we consider the many facets of the September birthstone...

Read more


A First Time Visit to Intenational Jewellery London 2019

A First Time Visit to Intenational Jewellery London 2019

Gem-A’s communications assistant, Olivia Gillespie, reflects on her first experience at one of the UK’s biggest jewellery trade shows, International Jewellery London.

Read more


Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


Buying Guide: Which Gemstones are in the Beryl Family?

Buying Guide: Which Gemstones are in the Beryl Family?

Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

Understanding Red Beryl

Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

Look at any list of the top 10 most famous gemstones in the world and you will undoubtedly come across the Star of India. Here, we find out more about this incredible star sapphire and discover its fantastical history, which reads like the plot of a Hollywood movie.

Read more


The Gems&Jewellery Autumn 2019 Issue Has Landed!

The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

Read more


Birthstone Guide: Peridot for Those Born in August

Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

Read more


Additional Info

Read more...

Diving into the World of New Zealand Paua Shells

Paua shells are the archetypal New Zealand gem - possibly even better known than its nephrite jade, known as 'greenstone', or Kauri copal, the fossilised resin or sap of the Kauri Tree. Here, Maggie Campbell Pedersen FGA looks to the ocean to learn more about paua shell, how it is farmed and how it is used in jewellery design. 

What are paua?

Paua belong to the large family of molluscs called Haliotidae, of which there are well over 100 species worldwide. Six are found in New Zealand, although only three are common. The most famous and exclusive to New Zealand is the Haliotis iris, known for the beautiful, vibrant colours of the inside surface of the shells. These colours range from striking blues through to aquamarines to greens, with tints of purple and gold. They are influenced by what the animal eats and therefore vary slightly from region to region.

Haliotis are marine gastropods. They carry one shell, and have one large, very muscular foot with which they attach themselves to rocky surfaces (in the case of H. iris the foot has a black outer skin). The name 'Haliotis' derives from the Greek, meaning 'sea ear', and along one side of the shells are small holes for expelling water in the aeration of the gills. The shell is made up of three layers: a very thin outer layer of conchiolin (a tough, insoluble protein secreted by molluscs, forming the organic matrix of the shell), under which is a chalky-looking rough material and beneath that is the coloured nacre (mother-of-pearl).

In common with other molluscs, the layers of calcium carbonate (in the form of calcite and aragonite) and conchiolin that form their shells, are laid down by the molluscs' soft bodies. Haliotis, however, lay down the inner layer of aragonite crystals and conchiolin in a slightly haphazard way, stopping altogether if the water temperature does not suit them. This results in areas where the conchiolin becomes very visible, giving an effect of wavy lines of organic material interspersed with beautifully coloured nacre.


A captive-bred, live mollusc ready to be harvested at a farm in Thailand

Where can paua be found?

Pauas live around the rocky coasts of New Zealand and are found at or below the level of the lowest spring tide, that is, at a depth of between one and 12 metres. Much of the paua used for gem purposes are wild-caught, under licence and to extremely strict quota. They can only be fished by free diving - no scuba is permitted - and only a certain number may be fished at any one time, all of which helps to keep the stocks of paua healthy. Furthermore, they may not be fished unless they measure a minimum of 125 mm at the longest part of the shell, which they usually reach at the age of about six years.

When did paua aquafarming start?

Paua aquaculture started in New Zealand in the 1980s. The captive-bred molluscs can be harvested when they are smaller - at about three years old. They are largely used for food, as the shells are not of quite such a vibrant colour. The outer, chalky surface of farmed paua is also pale blue (as opposed to the pale brown of wild paua), due to their feed. The soft bodies of farmed paua are slightly paler, which is considered more attractive as food - indeed the very black surface of the wild paua's flesh is usually removed before the meat is consumed.

The flesh of the paua is very rich in protein and has been a staple diet of the Maoris, who also used some of the shells in their carvings, almost always to depict eyes. In the large, wooden carvings that adorned Maori ceremonial houses and canoes whole shells were used, and were attached so that the inner, nacreous surface was visible (see below).

Paua shells used as eyes in a traditional Maori carving

How is paua used in jewellery?

The paua shell trade is unusual in that it is found at both ends of the market. It is well known in the form of colourful, whole polished shells, or inexpensive jewellery and trinkets, which are sold as souvenirs in museum shops and other such places. In jewellers' shops can be found the expensive paua shell items, set in precious metals and with gemstones (see below). At the inexpensive end of the market a little paua shell can go a long way when embedded in moulded clear plastic with a black backing, and is sold in great quantities to the tourist trade. It is made up into various designs, often depicting something specific to New Zealand such as a kiwi bird.


A paua shell necklace (left) and a 'Blue pearl', gold and diamond pendant by Catherine Best Ltd (right) 

When paua shells are sold whole, the outer, chalky-looking surface is removed to reveal the colourful, nacreous surface beneath, and it takes an expert only about 10 minutes to polish a raw shell on a diamond wheel (see main image). The typical pattern of the nacre with its dark, wavy lines of conchiolin is very attractive, and this is revealed when the outer layers of shell are removed. However, the inside surface of the nacre has a much smoother, almost liquid transition of colours, far fewer lines of conchiolin, and is subsequently considered the better material.

It is from there that the best pieces are taken to make jewellery, and is of course the area in which hemispheres of material are placed to produce blister pearls.

How are paua pearls cultured?

These blister pearls, also known as 'blue pearls', first came onto the market around the turn of the millennium.

These round blister pearls, usually referred to as mabés, are mostly produced from wild-caught paua, which are nucleated and treated in much the same way as the oysters in the culture of marine pearls, that is, by suspending them in baskets from lines in areas of clean water and tending them regularly.

The process of inserting the nucleus must be undertaken with utmost care as the smallest incision in the mantle can result in the death of the mollusc - they have no blood-clotting agent and therefore would bleed to death.

Natural paua pearls do exist, but they are always concretions produced by the animal outside the mantle and are inevitably very oddly shaped (see below). The success rate of the pearl production is not high. Only 10% will produce a marketable blister pearl covered with nacre, and only 2% will produce a smooth one of top quality and colour.


A natural paua pearl

Not only must the animals not be injured during the nucleation process, when the mantle is carefully lifted to insert the hemispherical bead underneath, they must then be kept in a stress-free environment for the two to three years it takes to cover the nucleus with nacre and produce a 'blue pearl'.

As with all organics, science alone cannot ensure success. We also have to rely on the assistance and co-operation of a living creature. ■

The full version of this article originally appeared in Gems&Jewellery July/August 2016 / Volume 25 / No. 4 pp. 10-12

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

All photos by Maggie Campbell Pedersen, except where otherwise stated


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

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Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

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Buying Guide: Which Gemstones are in the Beryl Family?

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Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

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Understanding Red Beryl

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Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

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Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

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We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

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Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

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Gem-A Student Celebrates Southend Success at Houses of Parliament

Second generation family business C J Vinten, was recently invited to exhibit its wares at the Houses of Parliament to celebrate a milestone for Southend. Angharad Kolator Baldwin reports…

Earlier this year, Southend-on-Sea was named as the Alternative City of Culture 2017. For family-run jewellery business C J Vinten, run by Gem-A student Lance Vinten and his sister Lily Vinten, this honour resulted in a unique opportunity to attend the Houses of Parliament.

Lily and Lance Vinten at Houses of Parliament
Lance and Lily Vinten in the Houses of Parliament with the C J Vinten Collection 

C J Vinten was chosen, alongside other local businesses, to represent the eclectic talents of Southend at a special gathering on 11 January. Gem-A was invited to witness this fantastic event, but also to learn more about the diverse talent that helped Southend earn the accolade.

Lance Vinten is the son of Christopher Vinten, who established C J Vinten Goldsmiths more than three decades ago. The jeweller, which can be found in Leigh-on-Sea Essex, includes a shop and workshop. When Christopher Vinten retired his children, Lance and Lily, took over the running of the business. 

Before studying at Gem-A, Lance attended the Birmingham School of Jewellery, completing the Jewellery and Silversmithing - HND course. Lily completed her Professional Jewellers’ Diploma with the National Association of Jewellers (NAJ).

Lance started his Gem-A journey with the Gemmology Foundation Online Distance Learning (ODL) course in 2015, swiftly followed by a Gemmology Diploma ODL course. Despite finding the course fascinating, the nature of distance learning made Lance crave conversation with other passionate gemmologists. To remedy this he attends as many of Gem-A’s Gem Central evenings as possible; noting that the “interaction with tutors, professional gemmologists and fellow students” is particularly enlightening.

Read more: Gem Central with Marcus McCallum FGA

When asked what he gained from the Foundation course, he commented that the program gave him a newfound interest in inclusions. He has also found being better at identifying stones, has given him new confidence when interacting with customers. 

This confidence was certainly on display at the Houses of Parliament, where C J Vinten Goldsmiths presented a wonderful collection of jewellery. This included an 18 kt white gold sapphire ring handmade by Lance himself.

Sapphire Ring C J Vinten
18 kt white gold sapphire ring. Image courtesy of C J Vinten

Also on display was a pair of silver dinosaur bone cuff-links and 18 kt white gold drop earrings, each rub-over set with a trillion cut pink sapphire and two brilliant cut diamonds. 

 

Dinosaur Cufflinks C J VintenSilver dinosaur bone cuff-links. Image courtesy of C J Vinten

 

Pink Sapphire Earrings C J Vinten18 kt white gold drop pink sapphire earrings. Image courtesy of C J Vinten

Lance commented: “We brought the pieces that Tom (the head craftsman), my sister Lily and I felt were the most impressive examples of our handmade work. We also wanted to show the range of jewellery that is made here [at CJ Vinten in Southend], to show that you don't need to spend thousands of pounds to get a nice one off piece. It was an honour to be involved in this event and to be invited as guests into the Houses of Parliament.”

For Lily Vinten, the highlight of CJ Vinten’s display was a red spinel and diamond ring, handmade in 18 kt white gold with an 18 kt yellow gold mille grain setting. The oval red spinel is surrounded by two steps of 62 brilliant cut diamonds. She told us: “After seeing many rings featuring vivid red stones in jewellery and fashion magazines and also the rise of Art Deco jewellery, we decided to create this stunning cocktail ring. The 1920s is famous for amazing dresses and jewellery, so with that in mind the craftsman came up with a design that would suit an evening gown.”


Spinel Ring C J VintenThe design process of making the red spinel ring. Image courtesy of C J Vinten

Lance believes continuing his gemmology education, and providing the opportunity for other staff members to continue theirs is “vitally important for the future of the company”. Recently CJ Vinten employed a workshop apprentice, who is already showing good potential, allowing Lance and Tom to pass some designs to her, as well as receive “copious amounts of tea”.

The Mayor of Southend, Cllr Judith McMahon gave a speech at the special event, hailing 2017 as “the Golden age”. She added in reference to Southend: “Art and culture is welcome, where it will flourish and find its natural home.” Looking at the wealth of talent in the room this certainly seems to be true. From folk dancing and confectionary to jewellery, the exhibition showcased it all. 

The Alternative City of Culture could not have come to fruition, without the dedication of Sir David Amess MP. A Member of Parliament for Southend West since 1997, he is determined to secure City Status for the town and propel Southend forwards. At the event he said it was a wonderful opportunity “to celebrate the rich culture and community of Southend”. ■  

The project has a 12-month programme of events arranged including art, sport and performance, making Southend the place to visit this year.

To view more of C J Vinten’s jewellery click here

Interested in attending a Gem Central event? For more information about our upcoming Gem Central events visit the Gem Central page or email events@gem-a.com.

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

Cover image 18 kt white gold cluster ring, claw set with Trillion cut morganite 1.52 ct, surrounded by Brilliant cut diamonds and further diamonds in split shank, 0.31 ct total, handmade by Lance. Image Courtesy of C J Vinten. 


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

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A First Time Visit to Intenational Jewellery London 2019

Gem-A’s communications assistant, Olivia Gillespie, reflects on her first experience at one of the UK’s biggest jewellery trade shows, International Jewellery London.

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Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


Buying Guide: Which Gemstones are in the Beryl Family?

Buying Guide: Which Gemstones are in the Beryl Family?

Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

Understanding Red Beryl

Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

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The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

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Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

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Inhorgenta 2017 Set to Impress with Gem Forum and Pearl Forum Seminars

Munich-based trade event Inhorgenta has taken its seminar content up a notch for 2017, incorporating a Gem Forum and its fourth annual Pearl Forum on the opening two days of the show.

The international buying event, which officially opens its doors on February 18, will welcome a plethora of speakers, including jewellery expert Joanna Hardy FGA DGA, GemWorld International president, Richard Drucker FGA (honorary), and pearl expert Dr Hubert Bari. 

Alongside its seminar programme, Inhorgenta offers its 'Carat' hall dedicated to gemstone, diamond and pearl wholesalers. The range on offer also includes natural geodes, discs and many other gemstone specimens. 

Assessing the gems on display at Inhorgenta Munich 2016

Inhorgenta 2017 Gemstone Forum schedule – Saturday 18 February 

Once the excitement of the morning has died down, Inhorgenta will present its Gemstone Forum, starting with a talk by Joanna Hardy from 2.30pm-3.30pm titled 'Coloured Gemstones in Jewellery Design Through the Ages'.  

This will be swiftly followed by 'Exploring the World for New Gem Discoveries' – a lecture by gemstone miner, trader and 'modern Indiana Jones', Yianni Melas. 

Melas is perhaps best-known for discovering 'Aquaprase'; a type of chalcedony that had evaded discovery until 2015. The Greek explorer discovered the bluish-green, translucent gem in Africa, although a more precise location remains undisclosed to the public. According to a report by the GIA, who authenticated the material: "Although chalcedony varieties such as chrysoprase and Gem Silica are well known and occur in yellowish green and greenish blue colours, the colour of this material was distinctly different from any African chalcedony examined by GIA to date."

The Gemstone Forum offer will continue with an update on gemstone treatments and deposits by Dr Claudio Millisenda (DGemG), who will conduct his talk at 3.30pm in German. Visitors can, however, benefit from a translation service played through a headset. Finally, the day one schedule will conclude with a talk by Gemworld International president, Richard Drucker FGA (hons), who will discuss 'Pricing Colour: The Methodology and Challenges'.

Any visitors to Munich who return to the show for day two, Sunday February 19, will also have the chance to experience the fourth annual Pearl Forum – a series of talks and seminars that have proved especially popular in recent editions of the trade event. Take a look at the video below to see Dr Laurent Cartier FGA sharing his words of wisdom at the 2016 Pearl Forum...

The theme for the 2017 Pearl Forum focuses on unexpected types of pearls, including finding innovative ways of using pearls in jewellery and creative means to market them. ‘The Rare and Unique World of Natural Pearls’ will be the first talk of the day at 10.30am, led by Dr Hubert Bari. Dr Bari is a graduate of the University of Strasbourg and a lecturer at the National Museum of Natural History in Paris. He has dedicated years to designing and organising exhibitions, and was the first to introduce audio guide systems more than 20-years ago. More recently, Dr Bari orchestrated the Pearls Exhibition, which travelled from Qatar to Tokyo in 2012, and later to London’s Victoria & Albert museum. 

A selection of pearls on display at Inhorgenta Munich 2016

At 11am, Douglas McLaurin, of Cortez Pearls, will discuss pearls from Mexico, followed by a discussion on ‘Pushing the Boundaries of Pearl Design’ by designer Melanie Georgacopoulous. Both of these lectures will be quickly succeeded by ‘Selling Pearls Online: Connecting with the Millennial Market’ – a talk by Pearl Paradise founder, Jeremy Shepherd. 

Read more: Diving into the World of New Zealand Paua Shells

Shepherd founded PearlParadise.com after discovering the world of pearls during his travels around Asia. Today, the digital company with its ‘farm-direct prices’ approach is worth a staggering $20 million, despite very little advertising.

The fourth annual Pearl Forum will conclude with a screening of ‘Power of Pearls’ – a film created by directors Ahbra Perry and Taylor Higgins of On the Reel Productions. The duo has travelled extensively to some of the most remote regions of the earth in order to learn more about pearls. Their film, which uses a combination of underwater, aerial and slow motion footage, will be formally premiered later this year. ■ 

Take a look at the trailer for ‘Power of Pearls’ below… 

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

All photos by Inhorgenta Munich, except where otherwise stated. 


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

Read more


Birthstone Guide: Sapphire for Those Born in September

Birthstone Guide: Sapphire for Those Born in September

Legend describes sapphire as a stone of honesty, trust and prosperity, bringing inner peace and protection to its wearer. Here, we consider the many facets of the September birthstone...

Read more


A First Time Visit to Intenational Jewellery London 2019

A First Time Visit to Intenational Jewellery London 2019

Gem-A’s communications assistant, Olivia Gillespie, reflects on her first experience at one of the UK’s biggest jewellery trade shows, International Jewellery London.

Read more


Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


Buying Guide: Which Gemstones are in the Beryl Family?

Buying Guide: Which Gemstones are in the Beryl Family?

Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

Understanding Red Beryl

Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

Look at any list of the top 10 most famous gemstones in the world and you will undoubtedly come across the Star of India. Here, we find out more about this incredible star sapphire and discover its fantastical history, which reads like the plot of a Hollywood movie.

Read more


The Gems&Jewellery Autumn 2019 Issue Has Landed!

The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

Read more


Birthstone Guide: Peridot for Those Born in August

Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

Read more


Additional Info

Read more...

Reconstructed Amber Broken Down

This article by Guy Lalous ACAM EG summarises a technical article from The Journal of Gemmology discussing the identification criteria for early (pre 2009) and current (post 2009) reconstructed amber, based on documented samples at the National Gemstone Testing Center (NGTC) in Beijing.

Newer amber material presents a serious identification challenge for gemmological laboratories. By comparing the structure of reconstructed amber with that of natural amber, is it possible to identify it? 

Read more: Diving into the World of New Zealand Paua Shells

Amber is formed from fossilised tree resin, but may have inclusions of animals, insects, plant debris, minerals, liquids and gases. The fossilisation process involves a progressive oxidation, where the original organic compounds gains oxygen, and polymerisation, which is an addition reaction where two or more molecules join together. This process produces oxygenated hydrocarbons, which are organic compounds made of oxygen, carbon and hydrogen atoms.

What is reconstructed amber?

Reconstructed amber consists of small amber fragments or scraps that have been reformed into larger pieces under heat and pressure. It is commonly manufactured from pieces of Baltic material. According to the process used, two main types of reconstructed amber exist:

Type 1 made without the addition of any substances to the amber fragments.

Type 2 which contains foreign substances (e.g. natural or artificial resins) that are added to make the material more solid and durable.  

Early reconstructed type 2 amber
13 mm diameter beads made of reconstructed amber containing foreign substances

What is Baltic amber? 

Baltic amber is fossil resin from coniferous trees. Baltic amber, also called succinate, contains 3-8% succinic acid. It was formed about 44 million years ago and today it is found in forests in Lithuania, Russia and Poland, where it is mined and exported in large quantities. The origin is confirmed by the presence of a ‘Baltic Shoulder’ in the fourier transform infrared spectroscopy (FTIR) spectra. Infra-red (IR) spectroscopy is the most effective scientific method for identifying fossil resins. 

What are the identification features of heated amber?

Heat-enhanced amber contains brownish flow lines. These flow lines result from the oxidation of pre-existing cracks that are healed during enhancement at low temperature and pressure, to solidify the raw material and to help avoid future cracking. The heating process will change the refractive index (RI) and infrared spectral readings. The higher the temperature used, the higher the RI will be, up to a maximum of 1.60. Exposure to greater temperatures may also alter some of the FTIR features: the ~1735 cm−1 absorption band shifts to down to 1716 cm−1, and the ~1157 cm−1 absorption band moves up to 1175 cm−1. The variations in RI and infrared spectra indicate that an amber specimen has been heated, but they do not provide conclusive evidence of reconstruction. 

Read more: Getting to Grips with GemTof Technology

When there is little or no foreign substance present, the FTIR spectra of reconstructed amber looks almost identical to that of natural amber, and additional examinations using a microscope, polariscope and UV lamp should be performed to make the proper identification. Most samples encountered at NGTC are type 1 reconstructed amber.  

What are the identification features of early reconstructed amber? 

Early reconstructed amber involved the use of relatively high temperature and pressure conditions in air. It is relatively easy to identify. The material displays a relatively dark body colour, poor transparency with a muddy-looking interior, and a diagnostic fragmental or mosaic structure (known as ‘blood streak’ in Chinese as it resembles blood vessels). The boundaries between fragments have oxidised (darker) edges that appear translucent brown or red. In addition to this some early-stage reconstructed amber may display uneven surface lustre, due to different hardness characteristics of the partially melted amber fragments.  

mosaic structure early reconstructed amber Heat enhanced amber

A 3-D mosaic structure in early reconstructed amber shows a network of angular boundaries that completely enclose the fragments. Below: By contrast, heat-enhanced amber displays brownish red flow lines that do not interconnect. Magnification 10x

How can you differentiate between natural and reconstructed amber?

Natural amber is amorphous and often shows anomalous double refraction in the polariscope, sometimes displaying snake-like, wavy or patchy extinction patterns. By contrast, early-stage reconstructed amber shows patchy grainy extinction, with clear grain boundaries and often exhibits interference colours. 

Natural amber usually displays even fluorescence, viewed with a UV lamp or in a DiamondView instrument. While darker-coloured early-stage reconstructed amber may not show diagnostic fluorescence, pale-coloured material commonly shows uneven luminescence with a fragmental or granular structure.  

What are the identification features of current-stage reconstructed amber?

Current-stage reconstructed amber is manufactured under relatively higher temperature and pressure in an oxygen-free environment. It is often subjected to post-processing treatments that are designed to conceal identifying features. These include inducing internal and surface cracks (by heating and cooling), polishing with coarse grit to create a matt appearance, darkening the surface colour (by baking), carving complex patterns and applying coloured coatings. Microscopic observation reveals that finer grains are typically used as raw material for current reconstructed amber. Usually showing a more subtle and fine-grained fragmental structure consisting of areas of pale colour are enclosed by dot-like edges. The dark-coloured grain boundaries are nearly absent and can only be seen with careful observation, the ‘blood streak’ structure is not apparent. The post processing treatments obscure the features observed with the polariscope, UV lamp or the DiamondView. 

opaque reconstructed amber

natural amber and reconstructed amber

Above: Viewed with a strong transmitted light source, this opaque reconstructed amber bead exhibits no ‘blood streak’ structure, although the angular fragments are still apparent. Below: Two beads in an amber bracelet consist of natural amber (left) and current reconstructed amber (right) display fuzzy grain boundaries with no ‘blood streak’ structure. The presence of small grains with angular boundaries is the key identification factor for the reconstructed amber bead. Magnification 16x (left) and 12.5x (right)

Conclusion

The most effective method to identify reconstructed amber from natural amber is microscopy, to observe the internal microstructure. The Polariscope and UV Fluorescence are useful auxiliary methods but cannot be used to reliably separate current reconstructed natural amber. 

This is a summary of an article that originally appeared in The Journal of Gemmology entitled ‘Identification of Reconstructed Amber from Different Periods’ by Haibo Li, Jie Liang, Taijin Lu, Jun Zhang and Jun Zhou 2016/Volume 35/ No. 4 pp. 320-328

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover image Flanky internal cracks, eviddence of post processing heat treatment in current reconstructed amber. All photos by H. Li


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

Read more


Birthstone Guide: Sapphire for Those Born in September

Birthstone Guide: Sapphire for Those Born in September

Legend describes sapphire as a stone of honesty, trust and prosperity, bringing inner peace and protection to its wearer. Here, we consider the many facets of the September birthstone...

Read more


A First Time Visit to Intenational Jewellery London 2019

A First Time Visit to Intenational Jewellery London 2019

Gem-A’s communications assistant, Olivia Gillespie, reflects on her first experience at one of the UK’s biggest jewellery trade shows, International Jewellery London.

Read more


Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


Buying Guide: Which Gemstones are in the Beryl Family?

Buying Guide: Which Gemstones are in the Beryl Family?

Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

Understanding Red Beryl

Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

Look at any list of the top 10 most famous gemstones in the world and you will undoubtedly come across the Star of India. Here, we find out more about this incredible star sapphire and discover its fantastical history, which reads like the plot of a Hollywood movie.

Read more


The Gems&Jewellery Autumn 2019 Issue Has Landed!

The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

Read more


Birthstone Guide: Peridot for Those Born in August

Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

Read more


Additional Info

Read more...

Field Trip: Screening for Tourmaline at the Oceanview Mine, California

Claire Mitchell FGA DGA takes a hands-on look at the Oceanview Mine, in the Pala mining district in California, USA.

Oceanview Mine is situated 2.5 miles northeast of Pala, on the northeastern slope of Chief Mountain, a short, scenic drive from Pala, California. Visitors to the area pass through landscapes bedecked with nurseries growing a multitude of produce and plants; turning off the main highway you pass through beautiful orange groves, finally reaching the dirt track which takes you up to the mine. 

Famous mines in this area also include the Tourmaline Queen, famous for its 'blue cap pocket' tourmaline, and Pala Chief Mine, famous for its kunzite. The area has been a source of gem materials since the 1870s; with its most active period being between 1900 and 1922. 

Claim was first made to the Oceanview deposit in 1907 by Frank A. Salmons. Since then, ownership has passed through several hands during its lifetime, and the mine is now owned by Jeff Swanger, who acts as CEO, owner and operator of Oceanview Gem Mine LLC. In its lifetime the mine has produced some of the best morganite specimens ever recovered in North America, as well as exceptional tourmaline and kunzite, with additional minerals of lepidolite, mica, apatite, quartz and feldspars.

Black Tourmaline from Oceanview Mine.
Black Tourmaline from Oceanview Mine. Sorted by Claire Mitchell

Today the Oceanview Mine is the only actively working underground mine in this district. The mine is also open to the public for a fee-for-dig, dump screening - which I gleefully attended in April 2016.

Read more: Last Chance to See the Record-Breaking Foxfire Diamond at the Smithsonian

Two things first struck me when I first arrived: firstly, the amazing view from the top of the site, and secondly the beautiful, perfumed smell of wildflowers in the air.

The set up for the mining experience was simple: there was a large dump pile of material which had been taken out of the mine by excavator, around which the screening equipment was situated.

Dump pile and sorting trays at Oceanview mine
Dump pile and sorting trays at Oceanview mine

When I first arrived I was allocated a position and screening equipment, and after a safety briefing I was instructed on the most efficient and proficient technique for screening the material. We were given four hours to work the pile; so using a bucket and small shovel I collected a full bucket and returned to my workstation. Two large wooden heavy wire screens allow you to 'sift' the material - the first screen (with the larger mesh) sits atop the second screen with a smaller mesh.

Material collected from the pile is placed in the top mesh, the smaller material of which then passes through to the second mesh. Any larger pieces in the top mesh are then washed and checked for gem-quality material and discarded or kept as required.

Claire Mitchell FGA DGA sifting and sorting the material at Oceanview Mine
Claire Mitchell FGA DGA sifting and sorting the material at Oceanview Mine

The material in the second screen is then washed and checked for gem-quality material. It is thrilling seeing glimmers of colour or good crystal form.

Read more: Getting to Grips with GemTOF Technology

After four hours of happy and productive sifting, it was time to assess the fruits of the day's labours. These included tourmaline (pink, green and black, or 'schorl'), mica, quartz, garnet and beryl. Sadly I had to leave behind some of the larger pieces such as the tourmalines in matrix due to weight restrictions on my baggage, which, whilst not 'gemmy', were still very interesting pieces.

Tourmalines in matrix at Oceanview mine
Tourmalines in matrix

Visitors can also experience a jeep tour of Chief Mountain, which not only offers some breath-taking views but also allows you to catch a glimpse of the active mine entrance and prospects, as well as views of other famous mines in the area. At the edge of the ridge you can see the Tourmaline Queen Mountain, and in the distance you can just about see other former mine workings. 

There is truly nothing better than digging for gem materials - it's a great visit, for both the experience and for the introduction into the techniques in sorting by this method. I thoroughly recommend this to anyone visiting the area - a bonus is the fantastic weather and beautiful countryside whilst there.      

This article originally appeared in Gems&Jewellery July/August 2016 / Volume 25 / No. 4 pp. 14-15

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover Image coloured tourmaline. All photos by Claire Mitchell. 


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

Read more


Birthstone Guide: Sapphire for Those Born in September

Birthstone Guide: Sapphire for Those Born in September

Legend describes sapphire as a stone of honesty, trust and prosperity, bringing inner peace and protection to its wearer. Here, we consider the many facets of the September birthstone...

Read more


A First Time Visit to Intenational Jewellery London 2019

A First Time Visit to Intenational Jewellery London 2019

Gem-A’s communications assistant, Olivia Gillespie, reflects on her first experience at one of the UK’s biggest jewellery trade shows, International Jewellery London.

Read more


Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


Buying Guide: Which Gemstones are in the Beryl Family?

Buying Guide: Which Gemstones are in the Beryl Family?

Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

Understanding Red Beryl

Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

Look at any list of the top 10 most famous gemstones in the world and you will undoubtedly come across the Star of India. Here, we find out more about this incredible star sapphire and discover its fantastical history, which reads like the plot of a Hollywood movie.

Read more


The Gems&Jewellery Autumn 2019 Issue Has Landed!

The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

Read more


Birthstone Guide: Peridot for Those Born in August

Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

Read more


Additional Info

Read more...

The University of Nantes Announces DUG Diploma to Be Taught in English for First Time

French gemmological education centre, the University of Nantes, has announced plans to teach its advanced gemmology program, also known as DUG (Diplôme d'Université de Gemmologie), in English for the first time. 

Teaching will be done in English from November 6 to December 8, 2017, followed by examinations in spring 2018 to offer convenience for international students. 

Based in the Upper Brittany region of Western France, the University of Nantes offers a number of courses with an emphasis on nurturing laboratory gemmologists. Students on the DUG Diploma will learn how to use lab tools, such as infrared, Raman and UV-visible spectrometers and a scanning electron microscope (SEM), under the tutelage of expert gemmologists. 

To complete the course, students are required to submit a short scientific study on a gemmological topic of their choice. This is then followed by an oral presentation, giving students the chance to discuss their work in more detail. 

Those interested in finding out more about the course are encouraged to contact Emmanuel Fritsch FGA (Hons) (emmanuel.fritsch@cnrs-imn.fr) and Benjamin Rondeau (benjamin.rondeau@univ-nantes.fr). 

Find out more about the history of Gem-A here

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

Read more


Birthstone Guide: Sapphire for Those Born in September

Birthstone Guide: Sapphire for Those Born in September

Legend describes sapphire as a stone of honesty, trust and prosperity, bringing inner peace and protection to its wearer. Here, we consider the many facets of the September birthstone...

Read more


A First Time Visit to Intenational Jewellery London 2019

A First Time Visit to Intenational Jewellery London 2019

Gem-A’s communications assistant, Olivia Gillespie, reflects on her first experience at one of the UK’s biggest jewellery trade shows, International Jewellery London.

Read more


Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


Buying Guide: Which Gemstones are in the Beryl Family?

Buying Guide: Which Gemstones are in the Beryl Family?

Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

Understanding Red Beryl

Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

Look at any list of the top 10 most famous gemstones in the world and you will undoubtedly come across the Star of India. Here, we find out more about this incredible star sapphire and discover its fantastical history, which reads like the plot of a Hollywood movie.

Read more


The Gems&Jewellery Autumn 2019 Issue Has Landed!

The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

Read more


Birthstone Guide: Peridot for Those Born in August

Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

Read more


 

 

Additional Info

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An Interview with Dr Jeffrey Post of the Smithsonian Institution

Claire Mitchell FGA DGA talks to Dr Jeffrey Post, chairman of the Department of Mineral Sciences and curator of the National Gem and Mineral Collection at the Smithsonian Institution, about advanced gem testing, the Hope diamond and the importance of donations to the museum.

Dr Jeffrey Post with an assortment of beryls, a tanzanite and an amethyst. Interview with Dr Jeffrey Post.
Dr Jeffrey Post with an assortment of beryls, a tanzanite and an amethyst

Q. Moving forward, how important do you feel advanced testing will be?

I think it's getting there - a lot has changed in the last 10-15 years, particularly when you look at the kinds of sophisticated research instruments that the various gem labs have now. These days you’ve got pretty smart scientists out there trying to figure out ways to treat and enhance stones, so it takes pretty smart scientists and good instrumentation to be able to detect these treatments and enhancements. Nowadays there are labs all around the world that are treating stones - sometimes you don't find out about certain treatments until quite a bit later - so we are in an ‘arms race’ of sorts. It's getting to be fairly sophisticated material science - the kinds of techniques that are being applied are ones that are not always easy to detect, and ones that we would never have imagined that could be done. 

Read more: Getting to Grips with GemTOF Technology

I and many others have made the argument for a long time that we need well-trained scientists working in some of these labs, because the nature and sophistication of what is being done is dealing in the scientific. I think it’s a shame that there isn't a really clear path for someone to pursue research in science that will be directly relevant to gems. 

However, GIA - along with a couple of other groups - have tried to get together some funding to hire post-doctorates to work on gem-related projects, and have provided hands-on training to people that have good backgrounds in chemistry, physics and material science. It's clearly a step in the right direction - in the end you get someone who has that scientific background, but who also has some experience working on gem materials and who has been introduced to the gem world.

I think that the gem industry has some responsibility to try to help fund more of the kinds of research that needs to be done, research which will ultimately benefit the industry. Look at beryllium diffusion treatment, for example. That was something that no one ever expected - who would of thought of diffusing beryllium into corundum to change its colour - it's a pretty sophisticated treatment that took some research to figure out and understand, and then to develop a way to identify it. The trade were actually behind on that process by several years before it was finally cracked. 

It should be thought of as a much longer term investment - thinking about the health of the industry. For the good of all of us we need to figure out ways to be sure that we are staying up to date with technology, research and developments in related scientific fields. 

Q. The Smithsonian carried out advanced testing on the Hope diamond. It was reported that the type of instrumentation that was used created a very tiny hole in the diamond - did it? Was it hard to make the decision to test it in that way?

I hate to say it but it did. The key words here are that the hole was very, very, very tiny - if you look at it under a microscope you still can't see it. However, the decision to test in that way wasn't hard, not once I knew what the technique entailed. We had a pretty good understanding of what we were doing, what the test would involve and how the diamond would respond to it. We have a saying at the Smithsonian, that every specimen in the collection is available for research because ultimately, why are we keeping these things if we are not learning from them?

The Hope diamond is a very rare, blue diamond that is a piece of the earth. We use minerals and crystals to learn something about the earth - the Hope diamond has its own story to tell us about how it was formed, where it came from and how it is different from other diamonds, so I think that the fact that we have it in the collection means that it is available for us to study.

The Hope diamond in the Time-of-Flight-SIMS instrument. Image courtesy of Jeffrey Post. Interview
The Hope diamond in the Time-of-Flight-SIMS instrument. Image courtesy of Jeffrey Post

Read more: Harrods Unearths 228.31 ct Diamond from its Vaults for Private Sale

It wasn't just me it was a measured and thoroughly assessed decision. All the way through the tests we kept a close eye on things and made sure that it was working the way we thought it would, and so yes, we knocked a few billion atoms out of there, but no one is going to miss those few billion atoms. 

In the end we learned a fair bit of information about the diamond. We got a lot of publicity after we did that experiment and I think part of the reason for that was that people never thought about the Hope diamond as anything other than a ‘cursed’ gemstone worth a lot of money, so I think for many it was an eye-opener to think of it as something that is worth studying. The fact that it stays in the collection means that we can continue studying it.  

The instrument we use is the Time-of-Flight Secondary Ion Mass Spectrometer (ToF-SIMS) - 10-15 years ago we would never have imagined being able to use such an instrument or for somebody to have one in their department, so who knows, 10-15 years from now what other instrumentation will come along? What other options for testing will we have access to, that are equally non-destructive? It's therefore nice to know that we can go back and continue to try and pull a few little pieces of information from the item and continue to learn its secrets.  

Q. How important is the private sector to the purchase of acquisitions?

It's absolutely critical as the Smithsonian is a public-private partnership. We end up depending very heavily on private donations, particularly endowments that people have set up. Some of these go back 100 years whilst some of them are more recent, so one of our goals is that we are always trying to build up our endowments to continue to support the work that we do. 

Typically the collection has grown not from what we have purchased but from what people have given, so the big private partnerships are the donations that people have given us to help build the collection. Sometimes they come in as a large collection of minerals, sometimes as a single piece of jewellery or a single gemstone. The Smithsonian has been around for a long time (by USA standards, anyway) and so if we continue to accumulate at a steady rate the collection will grow to an even bigger collection. 

Read more: Last Chance to See the Record-Breaking Foxfire Diamond at the Smithsonian

Luckily we have time on our side; we don't need to get everything right away. One of the great parts of my job is the feeling that you are part of something that has had a long history and will have a long future - it's a cool feeling to be a part of something that has longevity associated with it. It gives you context for the work that you are doing and allows you to relax a little bit and say “I don't need to get that thing this year”, or “I don’t need to sell everything to get that one thing”, because that one thing, even if it goes into another collection now, will still be out there. 

The Dom Pedro Aquamarine, cut from a large crystal mined in Minas Gerais, Brazil. Cut by Bernd Munsteiner and donated by Jane Mitchell and Jeffrey Bland to the Smithsonian in 2011. Photo Credit Don Hurlbert. Image Courtesy of Smithsonian Institution.
The Dom Pedro Aquamarine, from Brazil. Cut by Bernd Munsteiner and donated by Jane Mitchell and Jeffrey Bland to the Smithsonian in 2011. Photo Credit Don Hurlbert. Image Courtesy of Smithsonian Institution.

It helps me to realise that my job never really had a beginning and doesn't really have an end; you are just stepping in as a caretaker of sorts, you keep things going and hopefully you will do some good things that will result in the collection growing.

As the National Museum of the USA we don’t charge, and so there really is a sense that people feel like the museum belongs to them - there is no better situation than one where you're saying “it's your museum, it's your collection, here's what we would like to do.” ■

The full version of this article originally appeared in Gems&Jewellery July/August 2016 / Volume 25 / No. 4 pp. 28-33

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover image the Smithsonian's National Museum of Natural History on the National Mall in Washington, D. C. Copyright Smithsonian Institution


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

Read more


Birthstone Guide: Sapphire for Those Born in September

Birthstone Guide: Sapphire for Those Born in September

Legend describes sapphire as a stone of honesty, trust and prosperity, bringing inner peace and protection to its wearer. Here, we consider the many facets of the September birthstone...

Read more


A First Time Visit to Intenational Jewellery London 2019

A First Time Visit to Intenational Jewellery London 2019

Gem-A’s communications assistant, Olivia Gillespie, reflects on her first experience at one of the UK’s biggest jewellery trade shows, International Jewellery London.

Read more


Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


Buying Guide: Which Gemstones are in the Beryl Family?

Buying Guide: Which Gemstones are in the Beryl Family?

Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

Understanding Red Beryl

Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

Look at any list of the top 10 most famous gemstones in the world and you will undoubtedly come across the Star of India. Here, we find out more about this incredible star sapphire and discover its fantastical history, which reads like the plot of a Hollywood movie.

Read more


The Gems&Jewellery Autumn 2019 Issue Has Landed!

The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

Read more


Birthstone Guide: Peridot for Those Born in August

Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

Read more


Additional Info

Read more...

Whitby Jet: A Discussion of its Simulants

Sarah Steele FGA DGA discusses the many simulants of one of Britain’s most famous native gemstones, Whitby jet.

If imitation is the sincerest form of flattery, then Whitby jet must be a very desirable material indeed. I can think of perhaps 20-30 different materials, both natural and synthetic, which, at one stage or another over the years, have been described as Whitby jet.

We think of a 40-year period during the mid to late nineteenth century as the heyday in Whitby jet manufacture, and from a jewellery output perspective that is unequivocally true. However, the desire for Whitby jet, and the quest to imitate it, has its roots much further back in time. 

Read more: Reconstructed Amber Broken Down

Following the Scottish Gemmological Association’s Conference this year, delegates had the opportunity to visit the 'Celts' exhibition at The National Museum of Scotland. I couldn’t resist the opportunity to join them in having a closer look at the museum’s stunning collection of Bronze Age jet neckpieces whilst we were there.

Historically, many of these early pieces containing black beads with high organic carbon content were described as Whitby jet. Modern analytical techniques have shown, however, that these almost always contain a variety of materials - Whitby jet, certainly - but also oil shales, lignites and cannel coals, often within the one piece of jewellery. 

Inchmarnock Bronze Age necklace showing use of multiple black materials. Photo credit Alison Sheridan. Whitby jet
Inchmarnock Bronze Age necklace showing use of multiple black materials. Photo credit Alison Sheridan

Whitby jet is a material with which the demand for rough will always outstrip supply in periods of high production, and jet collection requires patience as it is reliant on coastal erosion. Are we then, in the Bronze Age some 4,500 years ago, seeing the first example of a Whitby jet simulant? It has to be noted that the prevalence of Whitby jet in the archaeological record during this period suggests that it is arguably one of the oldest economic resources in the British Isles.

Fast forward 2,670 years and the Whitby jet simulant market is a fascinating and booming industry. British society is participating in a national obsession with mourning. With the death of George IV in 1830, the Lord Chamberlain’s office dictates the dress code for the period, stating unequivocally that “the ornament shall be jet”. In 1830 the term ‘jet’ meant only one material: Whitby jet. The death of the Duke of Wellington in 1852 prompted the production of Whitby jet jewellery into overdrive - the 50 recorded workshops in 1850 swelled to 204 following the death of Prince Albert in 1861, as yet another wave of mourning swept the nation. 

Read more: From Elizabeth I to Elizabeth Taylor with John Benjamin FGA DGA

Demand for rough Whitby jet was beginning to outstrip supply and other options were needed. The main attraction of Whitby jet as a gem material was of course its deep black colour and liquid-like lustre, but more importantly its low specific gravity (SG) 1.2-1.3. It was fine to look ‘weighed down’ by the convictions of your expression of mourning, but it was practical if the seven strings of beads you wore to denote that you were the seventh daughter of a deceased father, didn’t weigh more than a few ounces.

Therefore, to be a convincing simulant of Whitby jet, the imitation material would need to be light in weight. Whitby jet is also a poor thermal conductor and so always feels warm, as heat is not quickly transferred away from the surface. Today we often describe jet as feeling ‘plasticky’, however, in the mid nineteenth century plastic was yet to be discovered. The simulant therefore needed to be light in weight, black in colour and a poor conductor of heat. 

Horn and tortoiseshell

In 1712 John O’Bisset discovered horn could with the application of heat, be moulded into various shapes. When cooled the shape was retained - O’Bisset had discovered the first natural thermoplastic material. Sheets of horn were put between hot metal plates in a press and pressure applied. Placing the warmed horn into moulds before applying pressure enabled the production of horn boxes, beakers and other items. With the application of black dye, pressed horn was a good candidate for a simulant of Whitby jet and many jewellery items were produced. 

Horn has a tendency to delaminate due to its layered structure, so loupe examination often reveals these layers, especially on the reverse of brooches. Any damage to the edges also gives a slight transparency to the damaged area, which is not seen in Whitby jet. The colour can often seem uneven and it is not possible to screw a brooch fitting into jet. Therefore a screw, often seen in horn, is always a sign of a simulant. 

Pressed horn jewellery items. Whitby jetThe reverse of a pressed horn brooch showing lamination and screw fittings. Whitby jet
Top: Pressed horn jewellery items. Below: The reverse of a pressed horn brooch showing lamination and screw fittings

It is also worth mentioning that tortoiseshell, like horn, is also a natural thermoplastic. Tortoiseshell, a much admired decorative material, derives not from a land tortoise but from certain species of marine turtle, principally the relatively small hawksbill. Tortoiseshell is unlikely to be mistaken for jet due to the mottled colour, but the SG and ‘plasticky’ feel are similar.

Bog oak

Whitby jet is a fossilised wood, so perhaps a wood product could also make a suitable simulant. Bog oak is not a specific species, rather a term that indicates wood that has been buried in a peat bog for thousands of years. The extremely low oxygen conditions of the bog protect the wood from normal decay. While the underlying peat provides acidic conditions where iron salts and other minerals react with the tannins in the wood, gradually giving it a distinct dark brown to almost black colour. 

Bog oak jewellery. Whitby jet
Bog oak jewellery

Bog oak occurs in many areas of the United Kingdom but jewellery usually originates from Ireland. It was produced from the early 1800s but became popular in the mid nineteenth century, reflecting the demand for Whitby jet, especially after 1852, when techniques to mass-mould and decorate the material (through the application of hydraulic or heated pressure to the dried wood) were invented. 

Although predominantly used for mourning jewellery as a cheap substitute for Whitby jet, bog oak was also worn to support Irish crafts, with pieces often carved or stamped with Gaelic motifs such as harps or shamrocks - symbols not normally found in mourning jewellery. Concentric rings are usually visible on the reverse of items as blanks were lathe-turned prior to carving. Loupe examination always show the ligneous nature of the wood and the lustre achieved is usually textured and dull.

Vulcanite

In 1839 Charles Goodyear discovered the method of mixing sulphur with rubber to form hardened or vulcanised rubber, called Vulcanite. The proportion of sulphur can be increased or decreased in order to vary the required amount of hardening accordingly. Between 25-50% sulphur gives a hard product with the familiar feel of plastic. There are many Victorian vulcanite objects, but the most common form is an imitation of Whitby jet used widely in the production of brooches, bracelets and necklaces. Vulcanite could be produced in almost any colour, although the predominant colours are black (ebonite) and brown. As a result, vulcanite was by far the most widely-produced Whitby jet simulant. Unlike pressed horn a thermoplastic materials which, if heated again can be re-moulded into a different shape. Vulcanite is a thermoset material which, after moulding becomes brittle and cannot be remoulded. 

Vulcanite can be distinguished from jet relatively easily. If the material has been exposed to light over time it loses its black colour and becomes khaki brown. When rubbed, vulcanite smells strongly of sulphur and brooch pins are usually screwed into position rather than glued. Chain links only show one or two splits depending on the link style as the link can be twisted open and then closed. In comparison in Whitby jet links, where every other link in the chain is cut and glued and will always show two or three cuts depending on the style of link. As vulcanite pieces were often moulded from jet originals the same design is seen regularly and, with experience, can be identified easily. (Please note: the ‘streak’ test on vulcanite will reveal a light brown streak similar to that of hard Whitby jet and so should not be relied on).

Examples of vulcanite jewellery. Items with little exposure to light remain black (left). Items that have been exposed to light show the typical khaki colour (right). Whitby jet
Examples of vulcanite jewellery. Items with little exposure to light remain black (left). Items that have been exposed to light show the typical khaki colour (right)


Bois durci

In 1855 Francois Charles Le Page secured a French patent for a method of combining blood albumen from slaughterhouses, with wood powder to form a plastic mouldable material he called bois durci. The wood dust (either ebony or rose wood), was mixed with blood, dried and then ground to a fine powder. The powder was placed in a steel mould and steam heated to 150-250°C in a powerful hydraulic press. After half an hour the mould was plunged into cold water. The resulting wood product was an extremely dense, highly polished and resistant thermoset material. 

Prince Albert plaque made from bois durci. Whitby jet
Prince Albert plaque made from bois durci

Le Page is reported to have used the marketing strapline “Anything Whitby Jet could do, bois durci could do cheaper and in brown”. The most common items available in bois durci today are circular plaques showing royalty or statesmen of the time. They are generally brown and often have bois durci stamped on the reverse.

French jet and Vauxhall glass

As far as Whitby jet imitations go French jet, along with vulcanite one of the most common. Glass items were also produced in large quantities during the Whitby jet heyday, primarily faceted black glass beads referred to as French jet. 

Its higher SG, vitreous lustre and glass moulding marks mean it is unlikely to confuse French jet with Whitby jet. However, because many of the designs were so innocuous, finding a nineteenth century piece of French jet and identifying it from a piece of black glass, used all the way through to the 1940s, can be difficult for collectors of the material. 

Vauxhall glass is often referred to as the English version of French jet, however all French jet was not of course produced in France! This thin highly reflective mirror glass was produced by a silvering process. The silvering is often seen on the reverse - either intact or in residual traces. 

The back of a Vauxhall glass earring: silvering visible on edges. Whitby jet
The back of a Vauxhall glass earring: silvering visible on edges

Spanish jet

Although all the above impacted the Whitby jet industry, it was a natural jet which was finally responsible for the industry decline. By 1870 the Whitby jet industry reached its peak, before catastrophically collapsing. There were undoubtedly a number of reasons. Some blamed the terrific demand, which had outstripped supply and lead to a fall in standards of workmanship, as many workers hadn’t had the basic training. The large number of simulants also cannot have helped, but the final death knell was heralded by the arrival from the continent of Spanish jet. It is hard to estimate how much of this material was imported from Asturias, but it is first documented in 1874 and many tonnes seem to have been available. 

The Spanish jet trade had flourished between seventh and sixteenth centuries, and whilst the Spanish supply undoubtedly had some very good quality rough material, it seems that Whitby imported a rather poor quality jet, often containing pyrite, making it unstable. Finished pieces degraded quickly, cracked and crumbled. As a result, consumer confidence in an already struggling product sector collapsed.

Three faceted bead necklaces, cracked and crazed beads, likely Spanish jet (left), Whitby jet, showing high lustre and sharp facet edges (centre), French jet with chips and abraded facet edges (right). Whitby jet
Three faceted bead necklaces, cracked and crazed beads, likely Spanish jet (left), Whitby jet, showing high lustre and sharp facet edges (centre), French jet with chips and abraded facet edges (right)


Decline of the industry

In 1889 the Whitby Gazette reported “It would have been better for the Whitby jet Industry, and better for art development, if the Spanish jet trade had never been known in Whitby”. Despite desperate measures to support the Whitby jet industry, such as a quality mark scheme, the industry didn’t recover. The mourning trend was well and truly over. 

In 1915 The Lady described the Whitby jet trade as “A somewhat funereal fetish of fickle fashion”. Poor recognition for the greatest lapidary trend our nation, and perhaps the world has ever seen. 

The beginning of the twentieth century may have heralded the end of the Whitby jet mourning jewellery trend, but it didn’t signal the end of the road for the use of plastics in jewellery. In 1899 we saw the introduction of casein formaldehye; milk curds hardened with formaldehyde giving us such famous trade names as Galilith, and of course in 1907 phenol formaldehye, with wood flour or other filler as powder gives us the trade name Bakerlite. Galilith and Bakerlite were never used to imitate Whitby jet jewellery - by this time (and forgive the pun) you wouldn’t have been seen dead in this outdated material.

It seemed like the end of the road for Whitby jet. The last apprenticed jet worker Joe Lyth died in 1958, and with him died the secrets of the Victorian era. However, the last 30 years or so we have seen a revival in fortunes within the Whitby jet trade. Today there are 11 manufacturers in Whitby town. As mentioned previously, demand for rough Whitby jet is high and patience is required for collection of beach material. This has allowed poor quality materials, primarily Siberian cannel coals and Georgian jet (both often referred to as Gagate) with its poor stability and high porosity to enter the supply chain. 

Georgian jet is becoming increasingly common as finished contemporary style jewellery made by Baltic amber manufacturers, and within the last 12 months as antique style beads from an undisclosed source. Attempts were even made to sell rough to unsuspecting workshops in Whitby. Experienced lapidaries however quickly identified the new foreign imposter. In Whitby we have no issue with Georgian manufactures producing items from their indigenous jet, but lack of disclosure of origin leads to the material being retailed as Whitby jet somewhere along the pipeline.

Nomenclature and appellation of origin is, as always, crucial to price. A good Whitby jet string of Victorian beads is worth £300 upwards, the Georgian imitation probably nearer £20, so caveat emptor!

As a lapidary in Whitby, I know that the Whitby jet trade will, as always fight back against the latest simulants. A true jet to rival the beauty or stability of Whitby jet has yet to be discovered, but it does make me proud to think that for the last 4,500 years Whitby jet has been held with such reverence that many have tried to emulate it. With the desire of the Victorians to find the perfect simulant, Whitby jet was in part perhaps responsible for the birth of the modern plastics industry, and therefore the modern world as we know it. ■

This article originally appeared in Gems&Jewellery May/June 2016 / Volume 25 / No. 3 pp. 16-20

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover image fine Whitby jet cameos including King Oswy and his bride (centre) and Bejamin Disraeli (right). Photo Credits Sarah Steele, except where otherwise stated. 


Gem-A at Hong Kong Jewellery and Gem Fair 2019

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Gem-A at International Jewellery London 2019

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28th International Jewellery Tokyo 2017

Gemmology and Diamond Tutor, Julia Griffith FGA DGA EG, and Gemmological Instruments Manager, Samantha Lloyd FGA EG, travelled to Tokyo to represent Gem-A at the 28th International Jewellery Tokyo (IJT) 2017 show, held 23-26 January 2017.

IJT is Japan's largest international trade show with over 1,300 exhibitors showcasing their wares at the Tokyo Big Sight Exhibition Centre. The show offers an excellent opportunity to engage professional and amateur gemmologists with Gem-A courses and establish connections between Gem-A HQ in London and members based on the other side of the world.

Tokyo Big Sight Exhibition Centre. Photo Credit Sam Lloyd. IJT blog post
Tokyo Big Sight Exhibition Centre. Image courtesy of Samantha Lloyd

The Gem-A stand at IJT 2017 was quintessentially British and visitors to the stand could purchase gemmological books and equipment as well as sign up for membership or courses. The Gem-A stand was unique at the show, as most offered retail or grading services to visitors. The space was staffed by Julia, Samantha, Naito Ayako, Gemmology and Diamond Tutor and representative of Gem-A in Japan, and some much appreciated volunteers, who all offered a friendly face to those passing by. 

Gem-A Stand a IJT 2017
Gem-A stand a IJT 2017. Image courtesy of Julia Griffith

During the show on 25 January Julia gave a seminar on 'The Colours You Can’t See; Exploring Fluorescence', which Ayako translated into Japanese. This talk was well attended and received positive feedback. It was a practical hands-on seminar where attendees were encouraged to view multiple samples and had the opportunity to 'oooh' and 'ahhh over sensational slides curated by Julia.  

The Colours You Can't See; Exploring Fluorescence. Image Courtesy of Julia Griffith. IJT 2017
The Colours You Can't See; Exploring Fluorescence. Image courtesy of Julia Griffith

Participants were taught what fluorescence is, the science behind it, the history of it, how to test for it and shown some gemmological examples. The lecture mainly focused on diamonds and how fluorescence can be used to distinguish between natural and synthetic diamonds, as well as spotting simulants. 

Read more: Harrods unearths 228.31 ct diamond from its vaults for private sale

Participants learned of more artistic uses of fluorescence, such as Maria Kovadi who utilises the fluorescence of diamonds in her jewellery collection, YouVdiamonds

Example of Maria Kovadi's use of fluorescence in her work. Image courtesy of Maria Kovadi. IJT 2017
Example of Maria Kovadi's use of fluorescence in her work. Image courtesy of Maria Kovadi

Also shown was the aesthetically pleasing display of fluorescent minerals delightfully named the 'Magic Spheres', a collection put together by Rene Bossevain. These are suspended from the ceiling within the Crystal Caves Museum in Queensland, Australia.

Magic Spheres in daylight above, Magic Spheres in long wave UV light. Image Courtesy of Crystal Cave Museum. IJT
Magic Spheres in daylight above, Magic Spheres in long wave UV light below. Image Courtesy of Crystal Caves Museum

A Gem Central evening on composites also took place on 25 January. This hour and a half practical based session, which was also translated into Japanese by Ayako, allowed Gem-A members and students based in Japan to experience Julia's vast gemmological knowledge in person. This talk had an impressive turn out and was by all accounts a great success. 

Julia Griffith Presenting: The Colours You Can't See; Exploring Fluorescence. Image Courtesy of Ayako Naito. IJT 2017Julia Griffith Presenting The Colours You Can't See; Exploring Fluorescence. Image courtesy of Ayako Naito

Read more: Gem Central with Marcus McCallum FGA

Those that attended the evening discussed what a composite is, and why composites are made in the trade. They heard about common composite examples and what they are made of. One example described was soudé stones. Attendees learned ways to detect these composites and were shown examples of soudé stones, where the colourless crown and pavilion are attached together with coloured glue to imitate other gemstones and cause the colours shown below. 

Selection of Soudé Stones: photographs from the front and behind, which reveal the colourless pavilion in the larger stones. Image Courtesy of Julia Griffith. IJT 2017
Selection of Soudé Stones: photographs from the front and behind, which reveal the colourless pavilion in the larger stones. Image Courtesy of Julia Griffith
Selection of Soudé Stones: photographs from the front and behind, revealing the colourless pavilion in the larger stones. Images courtesy of Julia Griffith

Julia also described garnet-topped doublets (GTD), and how to identify them. This photograph (below), which was taken by Julia, shows the contrast in lustre between the almandine garnet top and the paste pavilion at the junction plane where they join on the crown facets. A feature only seen in this type of composite, excellently illustrated.

Garnet Topped Doublet (GTD): Almandine garnet top and paste pavilion. Image Courtesy of Julia Griffith. IJT 2017
Garnet Topped Doublet (GTD): Almandine garnet top and paste pavilion. Image courtesy of Julia Griffith

While in Japan, Samantha commented on the exciting opportunity to experience a different culture and meet Online Distance Learning (ODL) and ATC students. She particularly enjoyed meeting one Japanese Foundation ATC student who told her they had signed up to the practical course workshop in London, just for the opportunity to visit Gem-A HQ.

Samantha also had fun on the monorail journey to the Tokyo Big Sight Exhibition Centre, which offers views of Mount Fuji. She also met Emi Okubo FGA, granddaughter of famous author Akira Chikayama who wrote The Dictionary of Gemstones. This useful reference guide for all keen gemmologists is available to purchase from Gem-A's Gemmological Instruments shop. 

The monorail journey to work. Image courtesy of Sam Lloyd. IJT 2017
The monorail journey to work. Image courtesy of Samantha Lloyd

IJT is an important event which allows Gem-A to share our extensive gemmological knowledge with other enthusiasts. Many visitors to the stand expected answers that would immediately enable them to identify specific stones, but what they left with was the understanding that the study of gemmology is very nuanced, and gem testing is a complex discipline. The more you learn about it, the more interesting it becomes. ■

Gem-A are already looking forward to the 29th IJT scheduled for February 2018.

If you are interested in attending this event click here

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

Interested in finding out more? Visit Gemmological Instruments where you can purchase Akira Chikayama's book or by contacting instruments@gem-a.com.

Cover image Gem-A Stand IJT 2017. L-R Sam Lloyd, Ayako Naito, Emi Okubo, Julia Griffith. Image courtesy of Sam Lloyd


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

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Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


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Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

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Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


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Look at any list of the top 10 most famous gemstones in the world and you will undoubtedly come across the Star of India. Here, we find out more about this incredible star sapphire and discover its fantastical history, which reads like the plot of a Hollywood movie.

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We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


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The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

Read more


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Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

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Field Trip: Exploring the Wonders of Myanmar

Gem-A member Patricia Campion reports on a recent gemmological field trip to Myanmar, highlighting her experiences of gemstone market places, the Myanmar Gems Museum, in Yangon, and seeing mushroom tourmaline for the first time.

On Christmas Day, our group met in Yangon for a gemmological tour of Myanmar organised by Pauline Jamieson for the Scottish Gemmological Association. Just before we left for Myanmar, our plans suffered a fundamental blow with the Government closure of Mogok to all foreigners due to local civil unrest. However, the organisers did a wonderful last minute job of rearranging our itinerary to ensure that we saw and did much to make up for missing out on the famed ruby mines.  

Read more: Gem Central With Gem Dealer Marcus McCallum

Our gem tour proper commenced in Myitkyina (pronounced My-chee-na), which is home to Myanmar's licensed amber markets. Much of the local amber is a distinctive deep red, although a wide spectrum of colour was available. Burmese amber deposits are considerably older than Baltic amber (up to 100 million years old) and the quality and clarity was high, with some very fine specimens containing preserved insects and plants. The market sold a wide variety of jewellery, carvings and beads as well as rough amber.

As is true all over Myanmar, traders were friendly and very pleasant but prices were higher than expected due to the proximity of the Chinese market.

Amber market in Myitkyina. Image courtesy of T. and M. Medniuk. Myanmar Blog Post
Amber market in Myitkyina L-R Moira Verwijk and Helen Plumb. Image courtesy of T. and M. Medniuk

We also visited some interesting local emporia specialising in jade and got our first glimpse at the many and varied hues available, from magnificent, almost translucent imperial jade through the spectrum of greens, greys and lilacs to white jade and almost transparent 'ice' jade.  

Read more: A Quick Guide to the Crown Jewels at the Tower of London

Arriving in Mandalay, we sallied forth into the infamous Mandalay jade market. Moving at speed through the crowded, cramped space where experts trade jade, we were surrounded by frenetic activity making it an unreal but truly exhilarating experience. In the lower octane atmosphere of the surrounding stalls outside the official jade market, pieces of rough jade could be purchased inexpensively.

Mandalay jade market. Image courtesy of T. and M. Medniuk. Myanmar Blog post
Mandalay jade market. Image courtesy of T. and M. Medniuk

Next we visited a family run business selling good quality Mogok ruby at reasonable prices. Their stones had received some heat treatment, but were lively and of good colour and devoid of fissure filling or other undesirable treatments. Later we met gem dealers who had travelled from Mogok, offering a large stock of mainly spinel, peridot, ruby and sapphire.

Star ruby and star sapphire were plentiful, with sapphire tones ranging from deep blue through purples and pinks to silvery grey and creamy yellow. While some stones were marred by rather crude cutting or damaged through poor storage (endemic across Myanmar it seems), the variety of colours available in spinel in particular, was superb.   

Read more: Getting to Grips with GemTOF Technology

The Myanmar Gems Museum, in Yangon, afforded us a wonderful overview of the many rich treasures of Myanmar. Emporia housed within the same building yielded deep green peridot and pale but very clean aquamarine as well as the usual spinel, ruby and sapphire. Many of us appreciated the colour zoned or bi-coloured unheated sapphires, considerably paler than the famed Burmese blue, but prices were prohibitive.

Sapphires, and potentially some spinels. Image courtesy of P. Jamieson. Myanmar Blog Post
Sapphires, and potentially some spinels. Image courtesy of P. Jamieson

Colourful zircons and sizable rutilated topazes were also plentiful. However, the highlight was the discovery of mushroom tourmaline - a remarkable phenomenon which occurs near Mogok. The ones we saw were grey to pale pink in colour and we also managed to unearth wonderfully colourful cross section slices.

Mushroom tourmaline specimen. Image courtesy of E. Passmore. Myanmar blog post
Mushroom tourmaline specimen. Image courtesy of E. Passmore

Our time in Yangon encompassed visits to the famed Mogok Street, where many gems are traded, and a whistle stop tour of Bogyoke Aung San Market (formerly known as Scott's Market) where we got our first real chance to see Myanmar golden pearls among other treasures. We also got the opportunity to trade ourselves and perching on stools on a street corner we were instantly surrounded by dealers. Their stock was again mainly ruby, spinel and sapphire both rough and polished, plus some wonderful but rather pricey zircons.  

Trading in Yangon. Image courtesy of T. and M. Medniuk. Myanmar Blog Post
Trading in Yangon, members of the trip in front L-R Melanie Medniuk, Moira Verwijk, Lauretta Sanders, Pauline Jamieson, Patricia Campion, Elizabeth Passmore with the traders behind. Image courtesy of T. and M. Medniuk

The expertise and insight of our guide, Duncan Baker, meant that we got an unparalleled glimpse into Myanmar's phenomenal world of gems during our trip. As we departed back home we all agreed that if Mogok reopens we will return to this lovely country with its fabulous treasures and wonderful people. ■

Adapted by the author from an article originally written for the Scottish Gemmological Association. 

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover image rough amber samples. Image courtesy of P. Jamieson


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

Read more


Birthstone Guide: Sapphire for Those Born in September

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Legend describes sapphire as a stone of honesty, trust and prosperity, bringing inner peace and protection to its wearer. Here, we consider the many facets of the September birthstone...

Read more


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A First Time Visit to Intenational Jewellery London 2019

Gem-A’s communications assistant, Olivia Gillespie, reflects on her first experience at one of the UK’s biggest jewellery trade shows, International Jewellery London.

Read more


Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


Buying Guide: Which Gemstones are in the Beryl Family?

Buying Guide: Which Gemstones are in the Beryl Family?

Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

Understanding Red Beryl

Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

Look at any list of the top 10 most famous gemstones in the world and you will undoubtedly come across the Star of India. Here, we find out more about this incredible star sapphire and discover its fantastical history, which reads like the plot of a Hollywood movie.

Read more


The Gems&Jewellery Autumn 2019 Issue Has Landed!

The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

Read more


Birthstone Guide: Peridot for Those Born in August

Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

Read more


Additional Info

Read more...

Ruby and Pink Sapphire from Aappaluttoq, Greenland

This article by Guy Lalous ACAM EG summarises a study of the geology, gemmological and physical properties of rubies and pink sapphires from Aappaluttoq, one of the last pristine spots on the planet not far from the arctic circle. 

What is the difference between metamorphism and metasomatism?

When rocks change because of an increase in the pressure and/or temperature of their surroundings, it is called metamorphism. When metamorphism is accompanied by a change in the chemistry of a rock, the rock is said to have been metasomatised. Metasomatism involves changes in mineralogy and structure along with the addition and/or removal of elemental constituents.

What are mafic and ultra-mafic rocks?

Both are igneous rocks. In essence, igneous rocks are formed through the cooling and solidification of magma. Ultramafic rocks are igneous rocks with low silica and gas contents which makes them very fluid. Ultramafic rocks are given names depending on whether they are intrusive or extrusive. Peridotite is the name given to intrusive ultramafic rocks, komatiite is the name given to extrusive ultramafic rocks.

Mafic rocks are mostly composed of pyroxene, calcium-rich plagioclase, and minor amounts of olivine. The mafic magmas are somewhat more viscous than the ultramafic magmas, but they are still fairly fluid. Additionally, they contain somewhat more gas than the ultramafic magmas. Gabbro is the name given to intrusive mafic rocks, whereas basalt is the name given to extrusive mafic rocks.

A range of colour and clarity is shown by these rubies and pink sapphires (0.61 - 2,37 ct) from Greenland's Aappaluttoq deposit. Image Courtesy of Bilal Mahmood
A range of colour and clarity is shown: rubies and pink sapphires (0.61-2.37 ct) from Aappaluttoq deposit. Image Courtesy of Bilal Mahmood

The corundum from Greenland occurs within a phlogopite-bearing metasomatic rock. The rocks at Aappaluttoq have been subjected to high-pressure, high-temperature metamorphism. The mineralisation at Aappaluttoq is hosted by a reaction zone that formed from metasomatic interactions between ultramafic rock (peridotite) and mafic rock (leucogabbro). The peridotite has low silicon oxide (45 wt.%) and contains various chromophore elements (particularly Chromium, but and also vanadium, iron and titanium). The leucagabbro has an aluminium-rich composition.

During regionals metamorphism, fluid interactions between the two differing rock types created a metasomatic reaction zone encompassing part of the peridotite, the leucogabbro and the contact zone between the two units. Upon regional cooling, the reaction zone formed significant volumes of stable phlogopite with corundum. The availability of chromium from the peridotite allowed the substitution of Cr3+ for Al3+ in the corundum, producing its pink to red colour.  

Read more: Exploring the wonders of Myanmar

Standard gemmological properties are consistent with metamorphic-metasomatic-type rubies and pink sapphires from other world deposits. Typical inclusion features consist of coarse particles and fine needles of rutile, as well as inclusions of mica, talc, pargasite, cordierite, sillimanite, plagioclase and boehmite. Healed fissures and twinning complete the story. Catapleiite, chlorite, cosalite, dolomite, magnesite, margarite, pyroxene and sapphirine were reported in a previous study.  

A translucent, whitish inclusion of talc commonly observed in rubies and pink sapphires from Greenland. Magnification x58. Image courtesy of C. P. Smith. Aappaluttoq Greenland.A translucent, whitish inclusion of talc commonly observed in rubies and pink sapphires from Greenland. Magnification x58. Image courtesy of C. P. Smith

Spectroscopy in the visible range yielded following data: weak-to-distinct lines were observed at 468 nm and at 475/476 nm along with faint lines at 659 and 668 nm, plus two strong lines at 692 and 694 nm (which appeared as a bright emission line at 693 nm).  

Read more: Reconstructed Amber Broken Down

In the mid-infrared region of the spectrum, some rubies and pink sapphires from Greenland showed distinct bands at approximately 3310 and 3075 cm−1 (and weak bands at approximately 2100 and 1980 cm−1). These features indicate the presence of boehmite, which was mostly concentrated along intersection tubules related to twinning and/or parting planes. Such absorption characteristics are helpful not only for identifying the presence of foreign mineral phases, but also for proving that a gem has not been heated. 

What about origin determination and treatments?

A genuine untreated ruby is increasingly rare and non-treated gems fetch a substantial premium. Proven origins such as Kashmir for sapphires or Mogok for rubies may considerably contribute to the value of a gemstone. The trade is therefore requesting origin determination from gemmological laboratories. It all started with a microscopic approach in the eighties and developed over time as chemical and spectroscopic criteria were introduced.

Initial sorting experiments of the rough gem corundum. L-R medium pink, red, lilac pink. Image courtesy of True North Gems Inc. Aappaluttoq, Greenland
Initial sorting of rough gem corundum. L-R medium pink, red, lilac pink. Image courtesy of True North Gems Inc.

Crystal growth characteristics, inclusion identification using a Raman microprobe and analytical tools such as Laser Induced Breakdown Spectroscopy (LIBS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) have been incorporated into the routine of gemstone analysis.

Consequently, access to chemical elements is gained at very low detection limits. The latest technological development Inductively Coupled Plasma Time-of-Flight Mass Spectrometry (ICP-MS-TOF) allows trace-element characterisation of gemstones for origin determination and treatment detection, is fit for age dating, inclusion studies and high-spatial-resolution chemical mapping of gems.  

Read more: Getting to Grips with GemTof Technology

The chemical composition of the Greenland rubies and pink sapphires is characterised by relatively high iron contents and comparatively low concentrations of titanium, vanadium and gallium. The iron content separates them from the majority of stones from marble-type deposits.

Rubies and pink sapphires from basalt-related deposits also contain relatively high iron, although correlations between other trace elements can help to separate them from those of Greenland. The iron content of our Greenland stones was similar to that of some rubies and pink sapphires from East Africa. Further work on the trace-element and isotopic composition of the Greenlandic material is ongoing and should prove helpful for origin fingerprinting. Certain mineral inclusions such as cordierite, cosalite and catapleiite may point to a Greenland origin.  

Aerial photo shows construction of processing plant and main workshop in Aappaluttoq deposit. Taken October 2015. Image courtesy of True North Gems Inc. Aappaluttoq
Construction of processing plant and main workshop, Aappaluttoq deposit. October 2015. Image courtesy of True North Gems Inc.

Modern mining techniques are planned to maximise production and minimise cost. The mine economics were modelled using only melee-sized rough gem material. Pink sapphire makes up approximately 60-80% of the production, with ruby making up the balance. None of the stones included in the study were heat treated. It should be expected that heated Greenland corundum will become available at some point. The deposit has the potential to make an important contribution to the global supply of ruby and pink sapphire for many years. 

This is a summary of an article that originally appeared in The Journal of Gemmology entitled ‘Ruby and Pink Sapphire from Aappaluttoq, Greenland’ Christopher P. Smith, Andrew J. Fagan and Bryan Clark 2016/Volume 35/ No. 4 pp. 294-306

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover image partially healed fissures composed of groups of isolated negative crystals. Magnification x55. Image courtesy of C. P. Smith


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

Read more


Birthstone Guide: Sapphire for Those Born in September

Birthstone Guide: Sapphire for Those Born in September

Legend describes sapphire as a stone of honesty, trust and prosperity, bringing inner peace and protection to its wearer. Here, we consider the many facets of the September birthstone...

Read more


A First Time Visit to Intenational Jewellery London 2019

A First Time Visit to Intenational Jewellery London 2019

Gem-A’s communications assistant, Olivia Gillespie, reflects on her first experience at one of the UK’s biggest jewellery trade shows, International Jewellery London.

Read more


Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


Buying Guide: Which Gemstones are in the Beryl Family?

Buying Guide: Which Gemstones are in the Beryl Family?

Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

Understanding Red Beryl

Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

Look at any list of the top 10 most famous gemstones in the world and you will undoubtedly come across the Star of India. Here, we find out more about this incredible star sapphire and discover its fantastical history, which reads like the plot of a Hollywood movie.

Read more


The Gems&Jewellery Autumn 2019 Issue Has Landed!

The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

Read more


Birthstone Guide: Peridot for Those Born in August

Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

Read more


Additional Info

Read more...

Birthstone Guide: Aquamarine for Those Born in March

Those born in March are lucky enough to have two birthstones: the beautiful blue of aquamarine and the mysterious red-spotted bloodstone. Here, we delve into the history and mystical properties of aquamarine and why this sky blue gem is said to be a talisman of good luck, fearlessness and protection. 

The blue hues common to this popular stone are fitting considering the Latin translation of aquamarine is 'water of the sea'. Legends describe it as the mermaid's stone, bringing luck to sailors and protecting them from the perils of ocean travel.

In crystal healing, aquamarine is thought to have soothing energy that quells phobias or irrational fears. It is also associated with the throat chakra and is said to help boost the confidence of public speakers.

Beryl Gem-A Archive. Aquamarine birthstone
Facetted Beryl from the Gem-A Archive

From a gemmological perspective, aquamarine is a member of the beryl family of gemstones, which also includes emerald, heliodor, morganite and goshenite. Aquamarine is distinguished from these gemstones by its pale blue to bright blue colour, caused by iron in its chemical composition.

Many aquamarines available on the market have been heat treated to enhance their colour. A yellowish, greenish or bluish-green beryl can be heat treated to produce a stable blue colour or irradiated to produce the yellow of heliodor.

Read more: Exploring the wonders of Myanmar 

Aquamarine displays pleochroism, which means its presents multiple shades of colour at once. Untreated aquamarine can be pale blue, bright blue, green and colourless. It has a hardness of 7.5 on the Mohs scale. 

Where is Aquamarine Found?

Aquamarine is mainly found in Africa and Brazil, however, the March birthstone can also be mined in Australia, China, Myanmar, Pakistan, Madagascar, Russia, USA and Sri Lanka. In the 1950s, a famous and historically-significant deposit of aquamarine was found in Minas Gerais, Brazil, and the gemstones recovered became known as Santa Maria Aquamarines. Many gemstones from this location are highly-prized for their unusually deep blue tone. Today, you may come across the term 'Santa Maria' used to describe a particularly lovely blue colour aquamarine. 

Distinguishing Features of Aquamarine 

Aquamarine often occurs as hexagonal-shaped long prismatic crystals, with striations and rectangular etch marks occasionally found on the prism surfaces. 

Beryl Aquamarine Crystal Rectangular Etch Pits on Prism Face. Image Courtesy of Pat Daly. Birthstone Aquamarine
Beryl Aquamarine Crystal Rectangular Etch Pits on Prism Face. Photo Credit Pat Daly.

Aquamarine's durability and plentiful supply makes it a popular choice among jewellery designers. It can also be fashioned into most cuts, making it a firm favourite with lapidaries. 

Read more: Meet Renowned Gem Cutter John Dyer

Although many cut aquamarines are free of inclusions, two-phase inclusions (liquid and gas filled), spiky cavities, and tubes parallel to the length of the crystal that look like falling rain are common.

Beryl Aquamarine Feather of Two Phase Inclusions. Image Courtesy of Pat Daly. Birthstone Aquamarine
Beryl Aquamarine Feather of Two Phase Inclusions. Photo Credit Pat Daly.

 

The Dom Pedro Aquamarine

Perhaps the most famous aquamarine specimen is the 10,363 ct Dom Pedro, which weighs an astonishing 26 kg. To this day, it holds the title of being the largest piece of aquamarine ever to be cut. It was specialists in Idar-Oberstein, Germany, who took on the challenge in 1992.

Discovered by three Brazilian miners in Pedra Azul, Minas Gerais in Brazil in the late 1980s, the original aquamarine was a metre-long. Accidentally dropped, the specimen fractured into three separate pieces - the Dom Pedro being the largest. 

In 1991, Jürgen Henn from Idar-Oberstein visited the owner of this large aquamarine crystal. In 1992 the stone went on the market and Jürgen asked his colleague Bernd Munsteiner to assess at the stone. Bernd sent his son, Tom Munsteiner and Jürgen’s son, Axel Henn, to strike a deal in Brazil and bring the stone to Germany. 

For a year Bernd worked on the stone, studying the crystal, drawing facet patterns, cutting, faceting and polishing, before transforming the rough stone into an incredible obelisk.

The Dom Pedro Aquamarine, from Brazil. Photo Credit Don Hurlbert. Image Courtesy of Smithsonian Institution. Birthstone Aquamarine
The Dom Pedro Aquamarine from Brazil. Photo Credit Don Hurlbert. Image Courtesy of Smithsonian Institution.

The Dom Pedro first went on public display in 1993 in Basel, Switzerland. Some years later, it was destined to be cut into many smaller stones, but it was rescued by Jane Mitchell, who generously donated the Dom Pedro to the Smithsonian National Museum of History in Washington DC, USA. 

Read more: An Interview with Dr Jeffrey Post of the Smithsonian Institution

This awe-inspiring gemstone is in the permanent collection of the museum, housed in the National Gem Collection Gallery. ■

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover image beryl aquamarine crystal. Photo credit Pat Daly. 


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

Read more


Birthstone Guide: Sapphire for Those Born in September

Birthstone Guide: Sapphire for Those Born in September

Legend describes sapphire as a stone of honesty, trust and prosperity, bringing inner peace and protection to its wearer. Here, we consider the many facets of the September birthstone...

Read more


A First Time Visit to Intenational Jewellery London 2019

A First Time Visit to Intenational Jewellery London 2019

Gem-A’s communications assistant, Olivia Gillespie, reflects on her first experience at one of the UK’s biggest jewellery trade shows, International Jewellery London.

Read more


Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


Buying Guide: Which Gemstones are in the Beryl Family?

Buying Guide: Which Gemstones are in the Beryl Family?

Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

Understanding Red Beryl

Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

Look at any list of the top 10 most famous gemstones in the world and you will undoubtedly come across the Star of India. Here, we find out more about this incredible star sapphire and discover its fantastical history, which reads like the plot of a Hollywood movie.

Read more


The Gems&Jewellery Autumn 2019 Issue Has Landed!

The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

Read more


Birthstone Guide: Peridot for Those Born in August

Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

Read more


Additional Info

Read more...

Discovering Unique Cameos of the Rainforest

Helen Serras-Herman takes a look at work by Rainforest Design, carvers of beautifully unique cameos. 

Standing apart from all cameos carved today are the unique, one-of-a-kind shell cameos by Rainforest Design. Carved in high relief, they are exotic in style and subject matter, and find their roots deep in the rainforests of Panama. 

Cameo brooch featuring a frog on heliconia plant, set in 18 kt white gold, displaying delicate open lattice-work. Cameo blogpost
Cameo brooch featuring a frog on heliconia plant, set in 18 kt white gold, displaying delicate open lattice-work.

Frogs, lizards, orchids, birds of paradise, lilies, hibiscus flowers, hummingbirds, macaws and toucans are some of the fauna and flora rendered so life-like and realistic that they grab your attention and keep you captivated. These cameos are intricate miniature nature scenes of exceptional beauty. 

Read more: Exploring the Wonders of Myanmar

Cameos are a fascinating form of gem carving, which depict faces or scenes with figures. The design is ‘raised’ above the background material in a relief style by removing matter from the surrounding surface. Shell cameos are commonly carved on layered materials, with a result similar to hardstone cameos carved in banded sardonyx, taking advantage of the contrasting colours. 

Set of two unmounted geckos, measuring 25 mm and 26 mm. Cameo blogpost
Set of two unmounted geckos, measuring 25 mm and 26 mm.

Cameos carved on shells first appeared during the Renaissance, but they became very popular during the eighteenth and early nineteenth centuries, when French and Italian carvers began using shells widely. Most of these antique cameos are skillfully carved with individual designs. The archaeological discoveries of the nineteenth century of the ancient civilizations brought renewed interest to ancient Greek and Roman mythological subjects, along with beautiful floral patterns. 

The Sobralia decora (‘Beautiful Sobralia’) orchid - a white earth-dwelling orchid whose flower only lasts one day - featured on a 40 mm cameo brooch which takes advantage of the two distinct colours of the shell. Set in 18 kt white gold with 0.73 ct faceted pink sapphires. Cameo blogpost
The Sobralia decora (‘Beautiful Sobralia’) orchid - a white earth-dwelling orchid whose flower only lasts one day - featured on a 40 mm cameo brooch which takes advantage of the two distinct colours of the shell. Set in 18 kt white gold with 0.73 ct faceted pink sapphires.

The orange and white-coloured King Helmet shells (Cassis tuberosa) came into Europe in the mid-eighteenth century from the West Indies, and the pink Queen Conch shells (Eustrombus gigas), also known as the Emperor Helmet shell, from the Bahamas. Today, among the favourite shells for carving are the Cassis rufa (Bull Mouth Helmet) and the Cassis madagascariensis, known as the sardonyx shell. 

Carvers of the Rainforest 

The carvers of Rainforest Design are the Embera-Wounaan, a semi-nomadic indigenous people born in the Darien jungle of Panama, the dense area to the east that shares its borders with Colombia. Women in the tribe create beautiful tightly-woven baskets, which are considered to be among the best baskets in the world. 

Read more: Diving into the World of New Zealand Paua Shells

The cameo carvers, all of whom are male, were taught shell carving by North American entrepreneur Andy Ike, who lives in Panama. For years Ike exported Queen Helmet shells (Cassis madagascariensis spinella) to Italy for the carving trade. Then he set out to find and teach local artists. The first carver he taught was Lider Pena, who in turn taught his brother and cousins. 

Wounaan cameo carvers. Cameo blogpost
Wounaan cameo carvers.

The carvers’ previous knowledge of carving the local tropical tagua nuts was a great asset. Tagua nuts are the fruit seeds of the palm tree varieties native to Panama (Phytelephas, from the Greek meaning ‘plant elephant’, and often known as ivory palms or tagua palms). Once they are dried and the brown skin removed the nuts looks very much like ivory, in colour and texture. 

Also known as ‘vegetable ivory’, tagua nuts are mostly carved as miniature sculptures in the full round, a design attribute that the Wounaan carvers brought to carving the shell cameos, as most of them are carved in very high relief. Carving shell, however, is a more complex endeavor compared to carving the tagua nuts. Even though the hardness of the tagua nut and shell is similar (around 2.5-3.0 on the Mohs scale), the taguas are tougher and more compact, whereas the shells are more fragile. The Queen Helmet shells also have at least two colour layers, ‘knuckles’ (lumpy growths) and curvature that the carver must take into consideration. 

Read more: An Exclusive Interview with Gem Cutter John Dyer

The process begins with Andy Ike selecting the shells. He cuts the blanks (the preforms) in ovals or other shapes and provides the Wounaan carvers with a ready-to-carve material. The carvers use Dremel® power tools with diamond and tungsten carbide burrs for rough pre-forming and carving. Finishing is completed with hand gravers and fine sandpaper, until they achieve a wonderful gleaming lustre on their carved surfaces. 

The extraordinary talent of the carvers impels them to create these miniature masterpieces, inspired by the beauty of the tropical rainforest. Recent pieces show open lattice-work, small open areas that give the carving more depth and a three-dimensional look. This piercing method, though, can be very risky during the carving process, as the shell may fracture or break. 

Design and Jewellery 

Many endeavours come to fruition thanks to the perfect timing of people and minds coming together. In 2004, Roslyn Zelenka, another expat American living in Panama, came onto the scene. At the beginning she was purchasing the cameos from the carvers and supporting their efforts, and was responsible for promoting and selling the cameos, as well as setting them into jewellery. 

A Lilium cameo suite, which is an intricate miniature nature scene set in 18 kt gold with akoya pearls. Centre cameo is 40 mm. Cameo blogpost.
A Lilium cameo suite, which is an intricate miniature nature scene set in 18 kt gold with akoya pearls.

But with time, Zelenka developed new design ideas, pushing the limits of the carvers’ capabilities. The inspiration always comes from the limitless fauna and flora of the rainforest and the cultural heritage of Panama, making them absolutely unique in the world cameo scene. 

Several pieces are designed and carved as a suite - a centrepiece with two or more pieces for a necklace, or matching earrings, carved with amazing accuracy symmetrically in mirror-style. Matching sets cannot be created from every shell, to achieve a five-piece suite it may take examination of between 700–900 shells, making these exotic beauties very rare indeed. All Rainforest Design® cameos, whether loose or set, come with a serial-numbered certificate of authenticity. 

Zelenka explores innovative designs and Andy Ike relates this information to the carvers before each carving begins, finding the perfect shell for each design. Once the cameos are finished, Zelenka collaborates with local goldsmiths and coordinates the creation of astonishing jewellery pieces, all skilfully produced. Some pieces are simple pendant/pin settings framing the cameos in 18 kt white or yellow gold and 950 silver; others, especially some of the necklaces, are amazingly complex multi-piece cameo suites set with faceted gemstones and multi-strands of delicate pearls and gemstone beads. 

Starfish cameo pendant displaying extraordinary high relief and taking advantage of the shell ‘knuckle’, showing high curvature on the reverse side. Measuring 28 mm, set in 18 kt gold. Cameo blogpost.
Starfish cameo pendant displaying extraordinary high relief and taking advantage of the shell ‘knuckle’, showing high curvature on the reverse side. Measuring 28 mm, set in 18 kt gold.

The types of jewellery offered for sale include necklaces, pendants, earrings, brooches, bracelets, cufflinks and even tiaras. 

Zelenka is also in charge of marketing these exotic pieces, under the name Rainforest Design, and placing them with Panamanian and US galleries, jewellery stores and authorised retail representatives. One such representative is US-based Elaine Rohrbach - an old-time friend and phenomenal gemstones dealer - of Gem-Fare, a company that exhibits at the annual Tucson gem shows, where Zelenka brings her latest creations to show. 

Three-piece set of lattice-work octopuses, each measuring 31 mm. Cameo blogpost.
Three-piece set of lattice-work octopuses, each measuring 31 mm.

I met Roslyn Zelenka over a decade ago, when she came looking for me after reading Anna Miller’s book Cameos Old & New. When she showed me the Rainforest Design cameos, I was astounded by their beauty, quality, fine detail and high-relief carving and, of course, their unique subject matter. Every year, when we meet in Tucson, I marvel at the new designs: tropical angelfish, starfish, octopuses, snakes, seahorses, turtles, quetzal birds, butterflies, dragonflies and countless exotic orchid styles, all set in beautifully crafted jewellery pieces, or sold unmounted -a designer’s dream palette. 

For more information about the cameos of Rainforest Design®, please visit the visually rich website at www.rainforestdesign.com. ■ 

This article originally appeared in Gems&Jewellery Nov/Dec 2015 / Volume 24 / No. 7 pp. 28-31

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover image a Cattleya Laeliinae orchid cameo necklace with intricate lattice work, set with rubellite tourmalines and raspberry pink garnets. All jewellery and cameos shown in the photographs by Rainforest Design®. All photos courtesy of Rainforest Design®. 


Gem-A at Hong Kong Jewellery and Gem Fair 2019

Gem-A at Hong Kong Jewellery and Gem Fair 2019

Hong Kong Jewellery and Gem Fair is only a few days away and we are getting very excited to meet visitors and colleagues from the jewellery and gemstone industries, and of course be dazzled by the many gemmological marvels that will be on show at this world-class event.

Read more


Birthstone Guide: Sapphire for Those Born in September

Birthstone Guide: Sapphire for Those Born in September

Legend describes sapphire as a stone of honesty, trust and prosperity, bringing inner peace and protection to its wearer. Here, we consider the many facets of the September birthstone...

Read more


A First Time Visit to Intenational Jewellery London 2019

A First Time Visit to Intenational Jewellery London 2019

Gem-A’s communications assistant, Olivia Gillespie, reflects on her first experience at one of the UK’s biggest jewellery trade shows, International Jewellery London.

Read more


Gem-A at International Jewellery London 2019

Gem-A at International Jewellery London 2019

International Jewellery London is just around the corner and all of us at Gem-A are hugely excited for what promises to be a scintillating showcase of jewellery and gemstones! Take a look at some of the exciting activities and events we have planned for this year's show...

Read more


Buying Guide: Which Gemstones are in the Beryl Family?

Buying Guide: Which Gemstones are in the Beryl Family?

Gem-A gemmology tutor Lily Faber FGA DGA EG takes us through the variety brilliantly coloured gems belonging to the beryl family.

Read more


Understanding Red Beryl

Understanding Red Beryl

Gem-A is pleased to have some fascinating red beryl specimens in the historic Gem-A Gemstone & Mineral Collection. Here, Gem-A senior gemmology tutor Rona Bierrum FGA DGA EG, explores what makes this rare member of the beryl family so special.

Read more


Famous Gemstones: The Star of India Sapphire

Famous Gemstones: The Star of India Sapphire

Look at any list of the top 10 most famous gemstones in the world and you will undoubtedly come across the Star of India. Here, we find out more about this incredible star sapphire and discover its fantastical history, which reads like the plot of a Hollywood movie.

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The Gems&Jewellery Autumn 2019 Issue Has Landed!

The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

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Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

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Birthstone Guide: Peridot for Those Born in August

Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

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