Julia Griffith FGA DGA EG, looks at tourmaline, the enchanting rainbow-coloured birthstone for October.

Tourmaline is the rainbow jewel of the gem world. No other gem is available in such an impressive array of colours. Paired with good durability and high lustre, this gemstone has become a favourite of many.

Tourmaline Colours 

The hues, tones and saturations of tourmaline seem limitless, ranging from soft shades to vibrant explosions of colour. The desirability of the colour has a huge impact on price. The more vivid, rarer colours reach higher values, such as the coveted electric-blue copper bearing Paraiba tourmaline.

Read more: Gem-A confirms oldest known carved tourmaline

Many tourmalines have commercial names such as rubellite for pink to red tourmaline. It is also common to describe them simply with the pre-fix of their colour i.e., 'pink tourmaline'.

Parti-Colour Tourmalines 

Tourmaline is also known for its colour-zoned or "parti-coloured" specimens, where different zones of colour can be seen in the cross-section or down the length of the crystal. These can be cut to display the different colour patterns either as slices, creative carvings, facetted or cabochon gemstones, or left as whole crystal specimens. The most popular colour-duo is watermelon tourmaline which display pink on the inside and a rim of green on the outside.

Bicoloured tourmaline on quartz. Image: ©Gem-A

Tourmaline is a complex boro-silicate of aluminium, magnesium and iron and the vast selection of colours are due to trace impurities and colour centres. The availability of these impurities may vary during growth, which allows for the development of different layers of colour.

Read more: Getting to grips with multi-colour gemstones

Its chemical makeup is so complicated that it cannot be synthesized, and is therefore always of natural origin.

Tourmaline Crystals 

The crystals are easy to identify with the tell-tale rounded 3-sided, or 6-sided, cross sections. They are often long and prismatic with heavy striations down the length of the crystal and are topped with either a pyramid or a flat pinacoid.

Watermelon tourmaline. Image by Pat Daly. ©Gem-A

Tourmaline Discovery 

First discoveries have been attributed to both Brazil and Italy in the 1500's. The name of tourmaline was derived from the Sinhalese phrase tura mali, which was used by the miners and traders to refer to "unknown stones of mixed colours". The advancement of mineralogy allowed the recognition of tourmaline as its own gem species in the 1800's.

Tourmaline Mythology

Since their discovery, tourmalines have been used as talismans for protection against toxins and radiation as well as many other healing properties which are associated with particular colours of tourmaline. They are said to emit far-infrared rays that penetrate the body and stimulate and soothe the tissue within.

This association is likely linked to the ability of tourmalines to become charged when heated, which is known as pyroelectricity.This property causes tourmalines to readily attract dust, and so a regular flick with a duster is recommended if they are displayed under hot lighting - arguably, a small inconvenience for such a stunner of a gem.

Facts about Tourmaline 

Tourmaline has a hardness of 7 - 7.5 and good toughness, making it suitable for use in jewellery. Inclusions are fairly common in tourmaline and many contain mirror-like fractures within them, which can be quite attractive, but may compromise the durability if knocked. Inclusion free stones are available and will fetch a premium price.

Parallel needle-like cavities are also common in tourmaline, which in vast numbers can create chatoyancy, or the "catseye", effect.

This article was written by Julia Griffith, FGA DGA EG at Gem-A for the Oct/Nov 2017 issue of The Jeweller - The magazine of the National Association of Jewellers

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 Tourmaline group. Image courtesy of Julia Griffith.

Download PDF of Volume 35 / Issue 7 / 2017

Read more AbstractAbstract Abstract Abstract

Point Point Point Point

Guy Lalous ACAM EG explores a detailed characterization of Baltic amber samples treated in experiments by Wang et al.(2014) in The Journal of Gemmology, whilst discussing the criteria for identifying heat-treated amber using standard gemmological instruments, FTIR and Raman spectroscopy.

Amber is an organic gem. Organic gems are the products of living or once-living organisms and biological processes. The fossilisation process of amber 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 about “Beeswax amber”?

Beeswax amber is sub-translucent or opaque due to abundant microscopic bubbles.

(a) Surface features of aged beeswax amber may include oxidation cracks, as shown here on sample JD-2; note the unoxidized centrelines and only minor 'bleeding' of adjacent colour. (b) By contrast, cracks formed in beeswax amber during natural weatheing have dark centrelines with more extensive 'bleeding' of colour, as seen here on untreated amber JB-3. Photomicrographs by Y.Wang; magnified 20x.

What about “Sun spangles”?

In heat treated amber, discoidal stress fractures are produced by expansion and decrepitation after the pressure equilibrium of the bubbles within the amber has been abruptly broken. Those fractures are referred to as “Sun spangles”. The presence of large and numerous sun spangles within amber provide immediate evidence of heat treatment.

What about treatments?

The main purposes of amber heat treatment are to improve or alter the colour, enhance the clarity and produce inclusions that have an appealing visual effect (“Sun spangles”). Methods include clarifying, baking (oxidation), decrepitating and ‘beeswax ageing’.

This paper provides a detailed characterization of Baltic amber samples that have been treated in experiments by Wang et al.(2014). Standard gemmological instruments were used as well as FTIR and Raman spectroscopy to document changes in the physical, optical and spectroscopic properties of the samples before and after treatment. The formation mechanisms of the features seen in heat treated amber are discussed, and criteria for identifying heat-treated amber are presented.

'Sun spangles', or discoidal stress fractures, were exhibited by heat-treated amber samples that underwent decrepitation. They are shown here within: (a) golden fire amber JE-5 (magnified 15x) and (b) red fire amber JC-3 (20x; the red colour of this particular discoid fracture is partially obscured by yellow reflections from the surrounding amber). Photomicrographs by Y.Wang.

What about the “Baltic shoulder”?

Infra-red spectroscopy is the most effective scientific method for identifying fossil resins. With this technique broad absorptions will be witnessed in Baltic amber in the 1260-1160 cm-1 range. Those are assigned to C-O stretching vibration. These features known as “Baltic shoulder” are specific to Baltic amber and are related to the presence of succinic acid. Baltic amber, also called succinate, contains 3-8% succinic acid.

The gemmological and spectroscopic features of untreated versus treated amber are listed in the table below:

(*) Progressively with clarification and oxidation

Untreated amber specimens from Kaliningrad Russia, were sliced into multiple pieces for heating experiements. Each sample number is shown with the total weight of all the slices. Photos by Y.Wang

Pictured here are the same samples in the pictured above following various treatment processes, as described in the text and in the table above. Photos by Y.Wang

What about the variations of the FTIR features after heat treatment?

A decrease of the absorption of the major band at 2932 cm-1 suggests that the saturated C-H bond was broken down by heating. An increase in intensity of the absorption at 1732 cm-1 suggests that oxygen involvement enables a higher concentration of the C=O functional group. The extinction of the weak absorptions at 1645 and 888 ccm-1 corresponds with the breaking of the unsaturated C=C double bond of the exocyclic methylene group. Heat treatment leads to fewer saturated C-H bonds and unsaturated C=C double bonds in amber, in correlation with more oxygen-bearing functional groups and higher degree of polymerization.

What about the variations of the Raman features after heat treatment?

FT-Raman spectra indicate that the number of saturated C-H bonds (1444 cm-1) consumed by oxidation during amber heat treatment is greater than that of unsaturated C=C double bonds (1645 cm-1) consumed during the process, and thus higher intensity ratio (I : 1645 cm-1/I = 1444 cm-1) indicate a greater degree of oxidation.

Representative FT-Raman spectra are shown for sample groups JA and JD, both before and after heat treatment.

What are the conclusions reached for the spectral intensity ratios after heat treatment?

FTIR: An intensity ratio of ≤ 1.54 for the 2932 and 1732 cm-1 bands is indicative of clarified amber, while ≤ 0.50 correlates to baked amber, the range of ~ 1.5 – 1.9 is not considered diagnostic. Raman: The minor changes in intensity ratios are not considered as being diagnostic for identifying heat treatment.

The treatments of amber are increasing in number and complexity. Baltic amber is the most versatile when it comes to treatments.

This is a summary of an article that originally appeared in The Journal of Gemmology entitled ‘Gemmological and Spectroscopic Features of Untreated vs. Heated Amber’ by Yamei Wang, Mingxing Yang, Shufang Nie and Fen Liu 2017/Volume 35/ No. 6 pp. 530-542

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: Golden amber pendant (upper left, 36.65 g), a bicoloured fire amber pendant (upper right, 22.59 g), a red amber necklace (96.27 g) and an aged beeswax bracelet (45.31 g). Photo by Y.Wang.

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The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more

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Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more

---

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more

---

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more

---

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more

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Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more

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Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more

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Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more

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Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more

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Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more

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In the last 12 months, an exceptional sapphire rush in eastern Madagascar saw thousands of people searching for precious treasure in one of the poorest places on earth. Rosey Perkins GG, an independent gemmologist based in London, shares this report from two visits to the island nation.

A sapphire rush that started in September 2016 has produced world class sapphires close to the village of Bemainty, in the wet forest of eastern Madagascar has reached upwards of 45,000 people. The mine site was in an area called Corridor Ankeliheny-Zahamena (CAZ), which is designated for conservation and managed by Conservation International on behalf of the Government of Madagascar.

I gained access to the mines near the village of Bermainty in October 2016 and May 2017 and was able to capture the lifecycle of the mines that has become known as 'Tananarive Carrier' (18°00'00"N 48°67'83").

'Tananarive', which is the capital city of Madagascar, refers to its size and 'carriere' is Malagasy for 'mine'. It lies 135km NE of the capital and is accessed via the nearest town of Ambatondrazaka. From here a motorbike can be taken to the trailhead at Ansevabe. On 21 October 2016, the President of Madagascar had declared the mining activity illegal because it was inside CAZ. I arrived at the mine the following day. There was a sense of urgency and camaraderie as the miners anticipated imminent government intervention.

1: 100ct sapphire from Bemainty Mines.

The gendarme were present at the site to keep peace and monitor the mining activity. The mine was highly productive and in Ambatondrazaka, I was shown high-quality blue sapphire up to 50g, as well as desirably-coloured pink-orange sapphires, reportedly mined at Bermainty (1). However, in February, the Swiss Gemmological Institute (SSEF) issues a trade alert with the warning that sapphires from these mines were being misreported as Kashmiri (Krzemnicki, 2017). A preliminary study of sapphires from this deposit indicated that the origin of these sapphires would prove challenging for laboratories and that more in-depth analysis was needed (Pardieu, 2017). For this reason, Lotus Gemology needed samples and so it was thanks to them and Association Française Gemmologie that I returned on May 6, 2017.

At 5am, I started climbing the path towards the mine and 10 hours later, we reached the valley that had heaved tens of thousands of people in October. It was a wide valley carved with pits but in May 2017 only about 500 miners remained. The southern end had been almost abandoned and work was concentrated in the more productive central and northern areas, where old pits two to three metres deep were being reworked. Miners had left due to illness, lack of funding or to return to their previous jobs. In the nearby valleys that had been explored, many groups hadn't found a stone for months. (2&3).

2. Tananrive Carrier facing North in October 2016.

3: Tananrive Carrier in May 2017. Image by Rosey Perkins.

However, the mining area had been a valuable source of income during the months that the local population had waited for the rains, which came later than usual. They arrived as miners, porters or cooks to feed the growing community. Soon the exploration had moved into the adjoining valleys, which were named Milliard 1-4. In May, shreds of blue tarpaulin attached to the top of poles marked abandoned claims and only the skeletons of abandoned huts remained. Morale was low in the valleys, but a few months earlier they had been a source of hope (4).

At Tananarive Carrier families lived in two story huts and many had tents on the first floor with shops beneath. These were stocked with beer, local rum, vegetables and plenty of meat. There was a hut for gambling, a cinema with a projector and a board of power sockets offering electricity to charge mobile phones. There were two churches and a mosque but still no school and no sanitation. A doctor had visited for the month of November but the gendarme (law enforcement) said another was needed.

4: Abandoned section of Milliard 3. 'Milliard is French for 'Billion' and a billion ariary (the currency of Madagascar) worth of stones - approximately £300,000 - had been found in each.

Trading was open and the gendarme was relaxed. At the start of the rush there were many independent 'cooperatives' but in May 2017 most were from other mining areas in Madagascar, such as Diego Suarez, Sakahara and Fort Dauphin. Mining activity was mainly sponsored by businessmen from the major cities. They financed another 'sponsor' who stayed at the mine and hired men in groups, providing food and equipment in exchange for first refusal on the stones they found. At Tananarive Carrier I met an independent sponsor who employed 16 miners, eight security guards and a woman who cooked their meals. His miners formed two groups and shared the use of a motor pump. He supplied the equipment for digging, the fuel for their motor and food for the men. He said he spent approximately $35 per week on rice and meat for the miners and expected to sell a sapphire with 30%-40% profit.

Ambodipaiso and Sahambato were two mining communities that had sprung up by miners leaving Tananarive Carrier (5). They had stopped at a river, camped and dug a test pit or panned for gold and found sapphires. Movement between them was fluid and, as a large sapphire was found at one site, the response was an influx of people (6).

5: Ambodipaiso on May 6th 2017. Image courtesy of Zanaky Ny Lalana.

As miners continue to explore this gem-rich earth of eastern Madagascar, there may be a great many more rushes in the area (Pardieu 2017). While the Government of Madagascar has declared the mining activity illegal, they have not brought it to a halt. The media's coverage of this story has not portrayed the gem industry favourably and, as mining continues, pressure will be on the gem and jewellery industry to respond.

Impact assessments are being carried out by independent consultancies on behalf of businesses sourcing gemstones in Madagascar and the response is likely to be rehabilitation programmes in areas of land damaged by mining activity. A collective effort to support conservation would help sustain Madagascar's biodiversity and also demonstrate the gem industry's commitment to responsible sourcing.

6: Sapphires from Sahambato which resulted in an influx of people to the area.

Acknowledgements: Permission to enter CAZ was given by the Prefecture D'Ambatondrazaka, Direction Regionale de L'Environment De L'Ecologie et de Forets and the Bureau du Cadastre Minier de Madagascar. The gendarme permitted our team four days inside the areas and gave us two policemen as security guards. Thank you to Institute Gemmologie de Madagascar, Association Francaise de Gemmologie, Lotus Gemology and Vincent Pardieu for their time and support.

Gem-A members can log in to read the full article Gems&Jewellery Autumn 2017 / Volume 26 / No. 3

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 team walking from Ansevabe towards the miners. Two gendarmes (local police) joined them as a security measure. In October 2016, Rosey had counted 1,000 people travelling towards the mine. In May 2017 we passed less than 50. All images by Rosey Perkins, unless otherwise stated.

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The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more

---

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more

---

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more

---

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more

---

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more

---

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more

---

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more

---

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more

---

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more

---

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more

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December 2017: An Update from the Author 

No matter how much any information has been checked prior to publication, it is always possible that – sooner or later - some facts are proved incorrect. An author may be contacted by a person who has read an article and has more information on the subject, and of course with time new research often uncovers new details that were simply not available when a book or an article was written. 

Whitby jet comes into the latter category as it has been the subject of research in recent years. We have long believed it to derive from the wood of one species of tree only (a species of Araucaria), but now research proves that it in fact derives from half a dozen or so tree or plant species. As yet nothing has been published about it, but we look forward with great anticipation to a paper on the subject. It is exciting news, and means that most of the accepted gemmological texts will need to be re-written. The updated knowledge does not, however, diminish the quality of good Whitby jet which is still of the highest order: very uniform, homogenous, deep black, and it takes a very high polish.

Since writing about corals in the Autumn issue of G&J, more information has come my way from Italy about the condition of the coral beds in the Mediterranean. I am assured that they are healthy, and that the fishing is now so tightly controlled by licencing and fishing methods (scuba diving only, size of coral permitted to be harvested, quota and permitted areas), that Corallium rubrum can be traded without a danger of over-fishing. These corals grow in deep waters, so are also less affected by changes in the sea temperatures and pollution. It is good to know that the situation is controlled and that we may continue to enjoy precious coral, but, as with all gem materials, I would always advocate buying only from a reputable source.

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A Connection to Coral: Gems&Jewellery Autumn 2017 Vol 26 No.3

Coral may not inspire the same emotional outpouring as ivory, but its delicate ecosystem needs to be protected, says Gem-A president Maggie Campbell Pedersen FGA ABIPP.

Coral has a long and rich history. Red coral has been found in Neolithic graves and two thousand years ago was much sought-after by the Chinese. The Ancient Greeks preferred black coral, while in some African countries red coral beads signified wealth. Few gem materials have been believed to have such powers as coral, both talismanic and medicinal. For example, it was thought that coral could cure madness, could strengthen babies' teeth, and that it turned pale when worn by someone who was sick. A piece of coral above the door of a house would protect its inhabitants, or its wearer from being struck by lightning.

Coral use today is more limited and consists of some jewellery and carvings. It does not have the same emotive impact as some other organic gem materials (notably ivory), yet it is understood that corals are vital to marine eco-systems and that they are threatened, and it should perhaps be remembered that they are animals, not plants - albeit tiny headless ones (called polyps).

The coral used in past times in Europe was predominantly the red Corallium rubrum (often termed 'precious coral' by the gem trade), mainly from the Mediterranean. In recent years we have used several different species of coral, originating from many different seas and oceans.

World-wide, coral beds are diminishing. Each species of coral needs different conditions to flourish, but all of them are extremely sensitive to alterations in the temperature of the water and in the acidity of the sea. Our coral fishing methods have been refined and we are far more aware of the risks of over-fishing, but the threats to corals of global warming and pollution remain, and many believe that corals are still being over-fished.

1: Different colours of Corallium corals.

Most corals consist of a white core - the 'communal skeleton' - made of calcium carbonate in the form of aragonite or calcite. They are covered by 'flesh' which consists mainly of tiny polps connected to each other by living tissue. In most corals the tissue also contains algae called zoolxanthellae with which the corals live in a symbiotic relationship. It is the algae that give the living corals their wonderful colours. In only a few of them is the calcium carbonate 'skeleton' coloured (1).

Global warming is causing ocean temperatures to rise, which can result in 'coral bleaching' - a phenomenon where large areas of corals reject their vital algae (zooxanthellae) and consequently die off, losing their coloured fleshy covering and leaving just the white skeletons. Corals grow very slowly - some at a rate of a few millimetres per annum - so it takes from 10 to 20 years for a reef to regenerate. As coral bleaching is today happening more often it is becoming less likely that the corals can recover, hence the worry about the Great Barrier Reef off Australia's north-east coast, and also the reefs around Belize.

The phenomenon affects reef corals because they grow in shallow water, however, of our gem corals only blue coral is a reef coral, and all other gem corals are either solitary or colonial in habit. They live on the seabed and grow at greater depths where they are less vulnerable to changes in the water temperature. Despite this, they are still sensitive to the raised acidity of the water and rising sea levels caused by global warming, and to all pollutants that find their way into the oceans. A further risk to their survival is physical impact which breaks them, for example caused by fishing nets, or divers. But perhaps their greatest threat has been over-fishing for the gem trade.

Corallium corals grow in colonies, and have a tree-like appearance (2). They range from white through shades of pink, salmon, and blood red to deep red. There are several Corallium varieties, of which C.rubrum is the best known. The Latin names of a number of the others are at present being changed - a frequent occurrence with corals. The colour in Corallium corals is in the hard skeleton, as they lack zooxanthellae.

2: Unpolished branch of Corallium rubrum showing the tree-like shape.

The coral is recognised by the tiny striations along its 'branches', which are still visible after cutting and polishing as they penetrate the entire skeleton. They are about 0.25-0.5 mm apart. The material takes a very high, porcelaineous polish (3).

Corallium coral is found in the Mediterranean and around Japan, China, and other areas of the Pacific. Fishing is now being regulated in several of these areas due to extremely depleted coral beds, and the rarity of the material is reflected in its price. It has been suggested that some Coralliums should be included in the CITES Appendices (the Convention on International Trade in Endangered Species of Wild Fauna and Flora), but this has not happened as the trade prefers to regulate itself. Methods being used include rotating areas where fishing is permitted, specifying the amount and minimum size of coral taken, the number of licenses granted, and the equipment used.

3: Detail of Corallium rubrum beads, showing structure and high lustre.

Torre de Greco (on the outskirts of Naples in Italy), has been a famous centre for coral carving for hundreds of years. Today the large companies cannot rely entirely on local coral to meet demand, so make up the shortfall - about 30%- from the Far East. The Mediterranean raw material is generally smaller in size, so larger items are carved from the Far Eastern material.

Several years ago at gem fairs such as those in Tuscon, bamboo coral (of the family Isididae), was sold in abundance, but today we see only small amounts for sale. A beige colour in its natural state, it is bleached and dyed, usually red or orange. It is a heavy material, and although the outer surface displays longitudinal striations similar to Corallium corals also have a growth habit resembling that of a tree, but they have nodes of organic material called gorgonian between the internodes of calcium carbonate. These characteristics limit the coral's use, and it is most commonly seen sliced into discs and used as beads, or as simple carvings. Occasionally it is seen imitating Corallium coral. It has been so popular that the coral beds are now severely depleted (5).

4: Bamboo coral: natural coloured rough, dyed rough, and dyed beads.

Heliopora coerulia or blue coral is found in many parts of the Indo-Pacific region and in the Great Barrier Reef. It appears on CITES Appendix II, indicating that it is permissible to trade but only under very strict conditions, and licences are required. It is a reef coral with a blue aragonite skeleton - one of only two reef corals with a coloured skeleton - and is massive in form rather than tree-like. It is covered in tiny holes in which the polyps lived (6).

6: Blue coral, Heliopora coerulia: rough and polished beads.

Some years back another red coral began to appear on the gem market: Melithaea ocracea. It is often called red sponge coral. It belongs to the family of soft corals, which create a less compact skeleton. Though it is still rigid, it is less stable as a gem material and is usually impregnated with a resin to stabilise it and to enable it to be polished to a satin finish. The resin also makes it much more comfortable to wear as it is a very rough material in its untreated state. It is naturally a red colour in the beige veins. It is found in the Indian and Pacific Oceans, and the China Seas (7).

7: Melithaea ocracea: polymer impregnated disc, colour enhanced beads (inner row) and reconstructed (chips in a red polymer, outer row).

Black and golden Antipatharia corals are found around the Philippines and Indonesia. They are also listed on CITES Appendix II. They differ from other corals in that their skeletons are made up of organic matter (closely related to keratin), not of calcium carbonate. Although flexible when growing, the material becomes rigid after fishing (8).

Golden corals are rare, but black Antipatharia can be bleached to a golden colour, and is often sold as a natural material. Once popular at gem fairs in the form of loose beads, black or bleached material is still occasionally encountered today, and is generally sold as 'old stock'.

There are other coral not mentioned here that can be used for jewellery or objets d'art, and not all are listed by CITES - often because they have not been adequately researched. It is incumbent upon the buyer or seller to check a species' status, which can be problematic as coral is notoriously difficult to identify when it has been cut and polished.

In the EU, licences must be obtained (e.g. from APHA, the Animal and Plant Health Agency in UK), for any corals that are listed by CITES on Appendix II. Each request is considered individually with many criteria taken into account. Other countries have different guidelines, sometimes stricter than ours, for example the beautiful Kulamanamana haumeaae golden coral from Hawaii is not listed by CITES, but is protected by US law.

8: Black Antipatharian coral, genus Leopathes: rough, and polished beads.

Some coral jewellery is still sold at the high-end of the market, beautiful items are still being produced in coral in the Far East, and there is still a coral industry around the Mediterranean, but generally not nearly as much coral is being worked today as in times past, partly due to fashion, partly due to the rarity of raw material, and partly because there are many people who feel that corals are too endangered and vulnerable should not be fished.

Attempts have been made at culturing corals, but so far it is a tiny industry, targeted mainly at the aquarist market where small corals are a popular addition to tropical fish tanks. Gem corals grow too slowly to make it a feasible alternative to wild-caught corals.

We do not emotionally equate the use of coral with that of ivory, but corals play a significant role in marine ecosystems and need to be protected, and failure to do so will eventually result in a total ban. Meanwhile the gem trade should ensure that any coral purchased is reliably sourced.

Gem-A members can log in to read the full article Gems&Jewellery Autumn 2017 / Volume 26 / No. 3

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: Corals for sale at the Tuscon fairs in 2008. All images ©Maggie Campbell Pedersen.

---

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more

---

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more

---

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more

---

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more

---

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more

---

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more

---

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more

---

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more

---

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more

---

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more

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Painter Angie Crabtree has built a reputation as one of the most sought-after diamond artists, literally recreating every sparkling facet in incredible detail. Here, she shares her passion for painting gemstones (and the occasional watch movement) with Gems&Jewellery...

With the job title 'Diamond Portrait Artist', Angie Crabtree has turned the facets of diamonds and gemstones into a thriving career. Her up-close-and-personal diamond paintings are flying off their easels, while Angie herself is in hot-demand for in-person event appearances and brand collaborations. Here Gems&Jewellery gets to the bottom of her fascinating career in the world of fine jewellery and precious gems...

What is your background and how did you begin painting diamonds?

My background is in art. I have been painting since I was four years old. I went to an arts high school and graduated from the San Francisco Art Institute in 2009. I also attended the School of the Art Institute Chicago and the Rietveld Academie in Amsterdam. I painted my first diamond - at 1.5m tall - in 2013 for a luxury-themed gallery exhibition in San Francisco.

Having known very little about diamond at the time, I began researching and found out that diamonds come in different cuts. This is where my continuous series of diamonds began!

What is it about diamond that has held your attention for so long?

Painting diamond portraits is meditative. I love learning about each one, and I love the abstract patterns and geometry. It's hypnotising! The symmetry, rainbow accents and reflections are so alluring. Every diamond is unique and presents a new challenge.

 How do people react to your work?

When I do live painting at special events, it is a great conversation starter. A handful of companies have commissioned me to paint their special stones, and invited me to paint at their event. Having a stone painted is a great way to show people the details in an up-close and personal way.

Where do you see your paintings progressing - will you be moving into coloured gemstones?

Absolutely yes! I recently started a series of fancy coloured diamonds behind-the-scenes, which I will be releasing sometime in the next year. Eventually, I will work my way to other gemstones and I really cannot wait. Recently I started painting close-ups of very detailed and unique timepieces. They are a new challenge, so I am excited to do more.

What can you tell us about the process of painting a diamond? Do you think people presume it is easier than it appears?

There is a lot that goes into the process that people cannot see just from looking at my Instagram account. Choosing the diamond, having it photographed, drawing the diamond, building the canvas, prepping the canvas, mixing the paint, base coats, layering, glazing, and weeks of drying time between coats. Even the photography is a big step; capturing the essence of my paintings - the exact colours and details - is no easy task.

Why do you think people are so enamoured with your diamond portraits?

I think people are initially interested in my work because diamonds are luxurious, but when they see them as painted works of art they become mesmerised in a new way. At least that is what drew me into the idea of painting them.

Originally, I was interested in exploring ideas of luxury through art, but after researching diamonds and gemmology, the whole series went in a new direction: it became more about getting lost in the abstract patterns, facets, reflections and colours - similar to how I fee; when I look into a kaleidoscope.

Are there any particular pieces you are most proud of?

My favourite piece is the painting I did of my engagement ring diamond. It is of an elongated emerald-cut that I picked out from my friends at Perpetuum Jewels in San Francisco. When I was searching for the perfect diamond, I knew it would eventually become a painting, so that is why I chose this one: I wanted to have a panoramic piece to hang in our home. It is the only piece I will never sell. I recently began selling phone cases printed with the diamond because, why not?! It is the perfect proportions!

What would be your advice to amateur artists who want to give painting diamonds and gemstones a try?

My advice would be to focus on not just the symmetry of the design, but also balancing of the colours and contrast. Mix all your colours from scratch so that they are in their purest form. Quality materials are important too.

Gem-A members can log in to read the full article Gems&Jewellery Autumn 2017 / Volume 26 / No. 3

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: Angie Crabtree with a selection of her diamond paintings. All images © Angie Crabtree.

Helen Molesworth FGA, managing director of the Gübelin Academy and a professor of the history of jewellery, takes the reader back in time to Seilam, now Sri Lanka.

'From here...we reach the island of Seilam, which is, for its size, one of the finest islands in the world...This island produces many precious gems, amongst which are rubies, sapphires, topazes and amethysts. The King of the island owns a ruby thought to be the most beautiful in the world, as long as the palm of your hand and as thick as three fingers; it shines like the most burning fire and is perfect.' - Livres des Merveilles du Monde or Book of Marvels of the World, Marco Polo, ca 1300

At the age of 17, a young merchant from a Venetian family set off with his father and uncle on an unusual expedition: to travel and explore the Far East. Twenty-four years later, in 1295, they returned to Venice, wealthy men, with a valuable hoard of both stones and stories. Immediately caught up in the Italian war to which they had returned, Marco Polo was imprisoned, and before his release, dictated his travels to a fellow inmate of posterity. What is passed down to us is a wonderful medieval European account of parts of Asia and the Middle East, from a unique historical perspective. Although relatively brief, the account of Sri Lanka, here Seilam, is extremely appropriate. It is an excellent early reference not only to the first known source of ruby (and maybe also and/or spinel, which was often confused in early sources) and sapphire at the time, but also to the beauty of the island.

A roman sapphire cameo, almost certainly from Sri Lanka, depicting Aphrodite feeding an eagle, first century. Image courtesy of the Fitzwillian Museum, Cambridge.

Known by the Greeks and Romans as Tabropane, in Persian as Serendib, and to be recognised more recently under British rule as Ceylon, Sri Lanka was often referred to by writers as a utopian land of natural riches and great beauty. The earliest gem reference to the island was as the origin for the valuable gems given by Middle Eastern King Solomon to the Queen of Sheba in the Old Testament. Centuries later, not far away in ancient Iraq, a wonderful oral tradition of fabulous story-telling developed in the Thousand and One Nights, in which we find the fantastic tales of continuous castaway Sinbad the Sailor, whose sixth voyage saw him shipwrecked on the very same island, where rivers flowed with rubies, diamond, pearls and 'many precious things'. From a western perspective, Sri Lanka's natural resources were already being traded into Europe through India by the time of Alexander the Great in the third century BC, thanks to the development of the Silk Route. By the time of Marco Polo's Livres des Merveilles du Monde, this fine island paradise was already clearly recognisable as an 'Island of Gems': the Ratna Dweepa of ancient Sanskirt.

A roman gold ring mounted with a sapphire, Sri Lankan, circa third century AD, Babar-Content Collection of Ruby, Sapphire and Spinel. Image courtesy of Medusa-art.com

All the more amazing are such early geographically-relevant accounts of sapphire when we realise that many seemingly ancient references to corundum are mistranslations or transliteration errors. Traditionally, European scholars have substituted our word (and European variations of) 'sapphire' for the ancient Latinised Greek or Persian versions of sapphirus, discarding modern day mineralogy in their translation efforts. In the majority of early references, such sapphirus would have been the blue lapis lazuli from the ancient mines of Afghanistan, and at worst case, any blue stone in general. The poor ruby suffers even worse the woes of inaccurate reporting. Often credited by non-historians today with being one of the Old Testament gemstones mounted in the High Priest's breastplate in the book of Exodus together with other marvellous ancient ruby references, in fact we have little to no archaeological evidence supporting the use of ruby as a gem so far back. Other red gems such as garnet, spinel, maybe; ruby, sadly not.

This highlights the importance of archaeological evidence supporting ancient references, and happily in the case of sapphire, a handful of important sapphires survive from antiquity. Several known Roman jewels exist, perhaps set in a ring with a single 'cabochon' polished pebble, such as the third century example from the Babar-Content Collection; and a few more tend to appear with other multi-coloured gems in later Byzantine jewels. Arguably one of the earliest and most beautiful is the Roman sapphire drilled as a bead and carved in cameo depicting Aphrodite feeding an eagle, a subject of imperial allegory from the first century and now in the Fitzwilliam Museum in Cambridge: an extraordinary important object, which would have been in the most prestigious of ancient collections.

The spoils of river mining in Sri Lanka: a collection of water worn sapphire pebbles.

By the Middle Ages onwards, naturally more sapphires survive, and unsurprisingly the best are found in royal collections. Two spectacular sapphires sit in the Imperial Crown of Great Britain: the seventeenth century Stuart Sapphire and the eleventh century St Edward's Sapphire, the oldest gem in the Royal Collection. Under Queen Victoria, both astonishing stones took pride of place at the front and atop the Imperial Crown. The huge hundred carat Stuart Sapphire sat central to the circlet, until it was bumped to the back by the Cullinan II in 1909, while the smaller St Edward's sapphire, eponymously and originally belonging to Edward the Confessor, remains in its venerated position, befitting its earliest owner, in the surmounting Maltese Cross.

Helen Molesworth trying out traditional faceting and polishing techniques with a bow drill in Sri Lanka. Image by Armil Sammoon.

Perhaps the most remarkable early medieval sapphires, however, were those mounted in the early ninth century Carolingian amulet known as the Talisman of Charlemagne. Said to have been sent to the Holy Roman Emperor by the Middle Eastern Abbasid Caliph Harould Al-Rashid, two sizeable sapphires once sandwiched a hair of the virgin as combined powerful symbols of purity, loyalty, royalty and righteousness. Exemplary too, of our Silk Route road for sapphire travels. These, and all those preceding, were almost undoubtedly examples of Sri Lankan sapphires, as Sri Lanka was, crucially, our only known source of sapphire in the ancient world.

I was fortunate enough to visit this incredible country recently, and to experience production and trade first hand on this 'Island of Gems'. Sapphires are still central, psychologically and financially, with a host of other gems, including garnet, moonstone, quartzes and spinel featuring frequently in local mining and manufacturing. I experienced main mining techniques directly, plus post production, in the regions surrounding Ratnapura, our traditional 'City of Gems', and from a historical perspective, it was remarkable to see hundreds, if not thousands, of years' practices continuing today as if through unbroken tradition.

Local miner with gem finds, Sri Lanka.

River panning for alluvial deposits continues almost unchanged, a millennial old mining practice which sorts surface-reachable deposits with relative ease. I descended shaft mines, also after secondary placers and another age old mining technique, which would have developed naturally after easier alluvial river beds would have been worked out. Watching the traditional blow-pipe heat-treatment of ruby buried amongst coke and coconut shell in a back yard reminded me of two medieval Arabic accounts - of Middle Eastern polymaths Al-Biruni and Teifashi - of burying Sri Lankan rubies within or under bonfires to improve their colour. Even some of the local cutting and polishing practices, with original hand-held bow drills, followed almost the exact same mechanism as a gem-carving drill depicted on one Mediterranean Roman gem-engraver's tomb from the first century AD.

Traditional heat treatment with blow-pipe and charcoal, Sri Lanka.

Yet Sri Lanka has balanced tradition with continual development. While quality of production and some traditional techniques have remained consistent for thousands of years, cutting-edge technologies have been developed and international trade drawn in from all over the world. At the same time as remaining a player on the world stage of gem production, Sri Lanka has successfully held off the loom of large scale mining giants ready to reap the riches of this tiny island below the surface, a forward-thinking decision in favour of local sustainable practices to give the country and its people a long term future.

This compact but competent land, long considered a natural utopia to travellers and traders, and once more coming into its own in terms of tourism, has consistently remained a true Island of Gems, a centre for sapphires, and indeed one of the 'finest islands in the world'.

Gem-A members can log in to read the full article Gems&Jewellery Autumn 2017 / Volume 26 / No. 3

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: Sapphire crystals from Sri Lanka. All images ©Helen Molesworth, unless otherwise stated.

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The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more

---

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more

---

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more

---

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more

---

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more

---

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more

---

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more

---

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more

---

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more

---

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more

---

The second largest gem-quality diamond ever discovered has been sold privately to Graff Diamonds for a staggering $53 million. 

First unearthed by the Lucara Diamond Corporation in the Karowe mine in Botswana, the Type IIa Lesedi La Rona diamond weighs in at 1,109 carats. It was initially put up for auction in June 2016, but after failing to reach its pre-sale estimate of $70m, stalling at $61m, the diamond was hidden away. 

Graff has a long-running reputation for buying big diamonds, including a 373 carat rough believed to be a fragment of the Lesedi La Rona in May 2017. The price was a cool $17.5m. 

Read more: Magnificent 51ct Dynasty Diamond Unveiled by Russian Mining Giant

The Karowe mine is also where the 813 carat Constellation diamond was uncovered in 2015. This particular diamond holds the record as being the world's most expensive, having been sold for $63m to a Dubai-based company. It is now in the hands of de Grisogono founder, Fawaz Gruosi, who is transforming the rough into as-yet-undisclosed masterpieces. 

Whilst the Lesedi La Rona diamond failed to sell at auction, it has now been privately sold to Graff Diamonds for $53m. ©Graff Diamonds

The 1,109-carat Lesedi La Rona is the second largest diamond in the world. ©2017 Lucara Diamond Corp.

Commenting on the purchase, Graff Diamonds founder and chairman, Laurence Graff, commented: "We are thrilled and honoured to become the new custodians of this incredible diamond. The stone will tell us its story, it will dictate how it wants to be cut, and we will take the upmost care to respect its exceptional properties. This is a momentous day in my career, and I am privileged to be given the opportunity to honour the magnificent natural beauty of Lesedi La Rona."

Lucara president and CEO, William Lamb, called the discovery of the stone a "company-defining event". He noted: "We took our time to find a buyer who would take the diamond through its next stage of evolution. Graff Diamonds is now the owner of the Lesedi La Rona as well as the 373-carat diamond... We are excited to follow these diamonds through the next stage of their journey."

High jewellery aficionados will now have to wait patiently to see what Graff Diamonds does with this incredible rough. 

Read more: Extraordinary emerald valued at $309 million is unearthed in Brazil

For further information and photos of the Lesedi La Rona visit lucaradiamond.com
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 1,109-carat Lesedi La Rona diamond sold to Graff Diamonds. ©2017 Lucara Diamond Corp.

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The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more

---

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more

---

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more

---

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more

---

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more

---

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more

---

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more

---

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more

---

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more

---

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more

---

At New Scientist Live, Barbara Kolator B.Sc. M.Sc. FGA DGA EG met with Dr. Leon Barron, senior lecturer in Forensic Science at Kings' College London about some innovative fingerprinting technology with implications for gemmologists, antique dealers, collectors and wildlife conservationists worldwide.

As you may have recently seen in the news, the UK Government intends to ban the sale of all ivory (with some exceptions). 

The team, including Dr. Barron from Kings' College, Mark Moseley who works with the Metropolitan Police, and David Cowdrey from IFAW (International Fund for Animal Welfare), has been instrumental in this ban with the development of a technique for the recovery of human fingerprints from ivory.

This kind of testing was identified as a priority in 2014 by Law Enforcement Agencies and the team furthered galvanised by a request from Mark's children that he should do something about elephant poaching. Since then the children have had the opportunity to demonstrate the kit themselves. It was also shown that at the US Embassy and IFAW currently fund kits to any country requesting them. So far at least 60 kits have been sent to 15 countries across Europe and Africa. 

Fingerprint testing kit. Image by Leon Barron.

How does it work and who is it for?

The technology is very simple. Normal fingerprints cannot be lifted from ivory, its odontogenic pores soak them up within a day or two. With this chemically tailored and finer magnetic powder, less fingerprint sweat material is needed and the powder can adhere to residues from 28 days previously, although they are still at their best quality within the first seven days.

The powder can be coloured for use on dark materials such as rhino horn. Jewellery made with rhino horn is now beginning to appear on the market. The kit has also been tested successfully on tiger claws, hippopotamus teeth, sperm whale teeth and even bird's eggs.

The kit costs £100 and comes in a robust lightweight field case suitable for use in remote or hostile range areas. Everything needed to carry out the forensic test is inside and the powder itself is relatively inexpensive.

Demonstrating fingerprinting kit. Image by Leon Barron.

The kits have been used successfully by the Kenyan Wildlife Service. Their use has already led to 15 arrests including those of five police officers. Border officials have also performed tests at airports when ivory has been found.

The kits have been validated to UK Home Office guidelines and excellent results have been obtained for individual identifications using in-service fingerprint databases.

28-day old fingerprint on ivory enhanced with reduced scale powder. Photo by Barbara Kolator.

In the absence of databases in several countries, Barron explained, fingerprints can also be used for comparison to those of known suspects to see if they are connected or can be excluded from the investigation. This helps with policing and enforcement even at a basic level.

The aim now is to gather large amounts of data to enable these databases to be built from the ground up. Fingerprint technology was chosen because it is simpler to use, but now even DNA can be extracted at a later date if required.

Why is this important?

The trade in illicit ivory is increasing and the UK is a major trafficking centre, with ivory from Africa going to Asia, passing through British ports and airports. In 2007 there were 11 seizures of ivory, in 2015 there were 345 including one of 100kgs at Heathrow Airport. This was the largest seizure in the UK. The unworked ivory and bangles were chopped up to fit into suitcases and were en route from Angola to Germany where they were going to be carved. 

Leon Barron at New Scientist Live. Image by Leon Barron.

So how will this novel technology impact gemmology and the antique trade? How will the industry respond? Is it worth remembering that the illicit trade in endangered species not only damages the planet but also involves organised crime terrorism on a global scale?

Is there a way of protecting and controlling endangered species, conserving ancient ivory works of art while at the same time making the trade of ivory so unprofitable and undesirable that it goes out of fashion? Perhaps this is a good time for some reasoned debate?

For more developments watch this space.

Electron micrograph of a reduced-size magnetic particle. Image by Leon Barron.

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 Examples of fingerprints enhanced on a full tusk, the top image complete with annotations. All images by Leon Barron unless otherwise stated.

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The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more

---

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more

---

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more

---

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more

---

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more

---

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more

---

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more

---

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more

---

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more

---

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more

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Guy Lalous ACAM EG summarises an article on inclusions in yellow danburite from Luc Yen, Vietnam, by Le Thi-Thu Huong, Kurt Krenn and Christoph Hauzenberger, originally published in Gem-A's The Journal of Gemmology. His report also examines optical characterisation of danburite and micro-Raman spectroscopy.

Danburite is a calcium borosilicate, CaB₂Si₂O₈, belonging to the orthorhombic crystal system. It is genetically associated with rocks of magmatic (granite pegmatite), metasomatic (skarn) and sedimentary (evaporite) origins.

This 31.6g danburite specimen from the Bai Cat alluvial deposit in the Luc Yen mining area shows eye-visible hollow tubes and overlapping 'fingerprint' inclusions. Photo by L.T.-T. Huong.

What about metamorphism, marble and pegmatites?

When rocks change because of an increase in the pressure and/or temperature of their surroundings, it is called metamorphism. Marble is a metamorphic rock primarily composed of calcite, formed when limestone is subjected to heat and pressure. Pegmatites are igneous rocks. Igneous rocks are formed through the cooling and solidification of magmas. Pegmatites contain extremely large crystals and rare minerals. Most pegmatites have a composition with abundant quartz, mica and feldspar.

Černy's scheme (1991) is the most widely used classification of pegmatites. It combines depth of emplacement, metamorphic grade and minor element content. It is divided in 4 main categories. The abyssal (high grade, high to low pressure), Muscovite (high pressure, lower temperature), Rare-Element (low temperature and pressure), and Miarolitic (shallow level).

The Rare-Element Classes are subdivided based on composition into LCT type (Lithium, Cesium, and Tantalum enrichment) and NYF type (Niobium, Yttrium, and Fluorine enrichment). The Rare-Element Class if further subdivided into types and subtypes according to mineralogical/geochemical characteristics. Many pegmatites fall nicely into these categories but some of the Madagascan pegmatites are virtually unique and don't fit into these categories.

Luc Yen is a mountainous district located in the north of the Yen Bai providence in Vietnam. Ruby, sapphire and spinel have been recovered from primary and secondary deposits since 1987 in the Luc Yen area. The geology of Luc Yen is dominated by metamorphic rocks - mainly granulitic gneiss, mica schist, and marble - that are locally intruded by granite and pegmatitic dykes.

This paper is an updated description of the inclusions in danburite from Luc Yen, which were characterised by optical means and by micro-Raman spectroscopy. The original source rock type for this alluvial danburite is then proposed, according to information provided by the study of the inclusions.

Internal features in Vietnamese danburite consist of fingerprints, hollow tubes, and two-phase and multiphase fluid inclusions. The two-phase inclusions were typically composed of a liquid and a vapour bubble that showed various proportions, suggesting heterogeneous entrapment of the dominant fluid during crystal growth.

Most of the multiphase inclusions contained several crystals, a liquid phase and a vapour bubble. The crystals in the multiphase inclusions typically formed colourless euhedral pseudohexagonal plates; some of them displayed interference colours.

(a) Primary  multiphase inclusions occur singly or are arranged along trails, both parallel and perpendicular to the c-axis of the host danburite crystal. (b) The CO₂ vapour bubbles in the two-phase inclusions vary in size, and in some cases only a thin layer of liquid is present along the inclusion walls. (c) Sassolite crystals in the multiphase inclusions appear as colourless, pseudohexagonal plates - sometimes displaying interference colours - with more-or-less perfect crystal faces. (d) Calcite crystals are occasionally associated with the sassolite plates in the multiphase inclusions. (e) This fluid inclusion contains multiple sassolite crystals accompanying two CO₂ vapour bubbles and a liquid (H₂O). Photomicrographs by K.Krenn.

What about Raman-spectroscopy?

In Raman spectroscopy the studied sample is illuminated with a monochromatic laser (single wavelength), the light is scattered by the sample. Light scattered from the sample is due to either elastic collisions of the light with the sample's molecules (Rayleigh scatter) or inelastic collisions (Raman scatter). Raman scattered light returns from the sample at different frequencies that are proportional to the vibrational frequencies of the bonds of the molecules in the sample. The Raman scattering from every molecule is different as the bonds for every molecule are different.

A Raman spectral 'fingerprint' can be generated. A database of reference spectra is necessary as the identification of a mineral by Raman spectroscopy is a comparative method. Raman spectrometry is useful to identify gems, inclusions and filling substances in gemstones.

What about sassolite?

Sassolite H₃BO₃, crystalline boric acid has been described for the first time as an inclusion in gas-liquid inclusions in minerals from the pegmatite veins Mika and Amazonitovaya in the Kukurt gemstone district in Central Pamir in 2000 (S.Z. Smirnov et al.). The crystals were rounded, tabular and less frequently idiomorphic with low refractive indices and high birefringence. The Raman spectrum of sassolite revealed an intense line near 880 cm^-1 and a weaker one at 449 cm^-1. The data obtained allowed reconstructing the conditions of formation of both granite pegmatites and hydrothermal systems where boron actively participated in mineral formation. Sassolite is a characteristic component of fluid inclusions in minerals from the majority of tourmaline-bearing and topaz-beryl miarolitic pegmatites.

Raman spectroscopy of the multiphase inclusions in the danburite samples revealed that most of the crystal inclusions were sassolite with occasional crystals of calcite. The sassolite showed two distinct bands at 500 and 880 cm^-1 and two additional bands at 3165 and 3247 cm^-1. The 500 and 880 cm^-1 bands are assigned to v_sB^[3] -O species, where B^[3] -O denotes three-coordinated boron. The calcite was characterised by two strong bands at 1088 and 283 cm^-1 and a less-intense band at 714 cm^-1.

The doublet at 270- 300 cm^-1 in the Raman spectrum of the calcite might result from a combination of the intense calcite band at 283 cm^-1 with the two nearby danburite bands (~281 and 296 cm^-1). The liquid and vapour phases were identified by Raman spectroscopy as H₂O and CO₂, respectively. The spectrum of CO₂ in the danburite fluid inclusions shows two diad peaks positioned at 1285.1 and 1388.3 cm^-1. The diad split (known as the Fermi doublet) corresponds to low-density values, which points to a granitic pegmatite source rock for the danburite.

(a) Micro-Raman spectroscopy of the danburite fluid inclusions in the 150-1500 cm^-1 range shows the presence of sassolite, calcite and CO₂ vapour. The black trace shows only the bands of the host danburite. Labelled peaks are from the inclusion phases present. (b) Raman spectroscopy of the fluid inclusions in the 1500-3000 cm^-1 range shows no bands from additional gas phases (e.g. N2 and/or CH₄), but only luminescence signals of the host. (c) In the 3000-3800 cm^-1 range, Raman spectroscopy of the fluid inclusions shows additional bands for sassolite (at 3165 and 3247 cm^-1) and characteristic bands of water.

The various proportions of a carbonic vapour phase (CO₂) compared to a liquid phase (H₂O) indicate a heterogeneous entrapment of the fluid inclusions. This suggests that the associated sassolite and calcite precipitated as a result of decreasing temperature through hydration reactions with the host danburite. The presence of sassolite together with low-density H₂O - CO₂ fluid inclusions indicates the Luc Yen danburite originated from a granitic pegmatite source rock.

This is a summary of an article that originally appeared in The Journal of Gemmology entitled ‘Sassolite- and CO₂-H₂O-bearing Fluid Inclusions in Yellow Danburite from Luc Yeb, Vietnam’ by Le Thi-Thu Huong, Kurt Krenn and Christoph Hauzenberger 2017/Volume 35/ No. 6 pp. 544-549

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: Hollow tubes in a 31.6g danburite specimen from the Bai Cat alluvial deposit in the Luc Yen mining area. Photomicrograph by L.T-T. Huong; field of view 2.5 cm.

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The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more

---

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more

---

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more

---

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more

---

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more

---

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more

---

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more

---

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more

---

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more

---

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more

---

Gem-A gemmology tutor Lily Faber FGA DGA EG takes a closer look at topaz, the birthstone of November, and explains why this gem should be high up on your Christmas wish list.

For those born in the cold month of November, topaz is a well-known and hopefully well-loved gemstone. For those born during the rest of the year, you may want to steal this birthstone for yourself!

Topaz History and Meanings

The name topaz most likely originated from the Sanskrit word 'tapas', meaning 'fire'. This gemstone is thought to promote creativity, increase sensitivity to taste to enhance your dining experiences, boost mental clarity and to uncover lies and illusions.

The ancient Greeks believed that topaz could render the wearer invisible - though I have yet to see proof of this effect! Topaz is the state stone for Texas and Utah in the United States of America and is the talisman for the astrological sign Sagittarius.

Blue topaz with incipient cleavage seen under table. Photo courtesy of Lily Faber, Gem-A.

Topaz Colours and Localities

Topaz is most often associated with the colours yellow, orange, blue or pink, but it can also be colourless, green and brown. Topaz comes in some of the gem world’s largest crystals that have to be measured in kilograms and not carats. A famous example is a single transparent topaz crystal from Minas Gerais, Brazil, which weighed 596 pounds.

Read more: Why Are Some Gemstones Associated with Bad Luck?

One of the most valued colours is known as 'Imperial Topaz', which is pinkish-orange to red-orange. Another highly valued colour is 'sherry topaz', which is brownish-yellow to orange or yellow-brown.

What about Imperial Topaz?

Topaz can be found in Brazil, Russia, Pakistan, Mexico, the USA, Madagascar and Sri Lanka. In the 19th century, the main source for pink topaz was in the Ural Mountains in Russia. The imperial family, including the tsars, reserved exclusive rights to own and wear the colour, thus imparting the name 'Imperial topaz'. It is less common than other naturally occurring colours of topaz and is thought to resemble the colours of the setting sun.

Red-orange and pink tones in a single topaz crystal. Photograph by Pat Daly, Gem-A. 

Historically, all yellow stones were called topaz, which has since been corrected, for the most part. In some shops, misnomers can still be seen today. Misleading names like 'quartz topaz', 'Scotch topaz' or 'Spanish topaz' are used for citrine quartz, so don't fall for it!

Topaz Colour Treatments

It should be noted that almost all pink topaz on the market today is mined in Brazil and heat-treated to bring out the pink colour. Natural blue topaz is typically pale, and stronger colours like 'London blue' or 'Swiss blue' are achieved by irradiating and heating a colourless topaz to promote and stabilize the blue colour.

One colour that was not created by nature is known as 'mystic' topaz. It is a colourless topaz that has been coated with a thin metallic layer to produce extreme iridescence.

Topaz Properties

Topaz is a relatively hard material, with a level of 8 on the Mohs scale of hardness. While it can take a high polish and show a bright vitreous lustre, its perfect and easy cleavage lets it down. Cleavage is a directional breakage that occurs along a crystal plane in only crystalline materials. 

Read more: Exploring the Varieties of Quartz

Topaz has what is called 'basal' cleavage, which is 90 degrees to the direction of crystal growth, or the c-axis. This breakage leaves a flat base (basal pinacoid) with the tell-tale terrace-like markings that look like tiny, wavy rivers running across the flat surface of the crystal. Any forceful knock or pressure can split the stone in two along this direction, so great care is taken when fashioning these stones. If wearing topaz set in a ring, it would be advisable to wear it in a rub-over setting to protect as much of the stone as possible. Otherwise, simply wear it in a necklace, earrings or, if you are feeling very fancy, a tiara.

Other things to know about topaz is that it's pleochroic, meaning it displays different colours in different crystal directions.

Topaz Inclusions

Topaz crystals are typically transparent with multiple straight, parallel striations running down the length of the crystal and a pyramidal termination at the top. They have a rhombus-shaped cross-section which looks like an elongated kite-shape.

Read more: What Career Paths Can Trained Gemmologists Take?

Inclusions can consist of healed internal fractures (feathers), long tube-like cavities and two-phase inclusions or a cavity with two immiscible liquids. Iridescence can be seen in both rough crystals and cut stones where there are internal fractures, or where cleavage is just starting to extend into the stone from the surface (also known as incipient cleavage). Also seen are variously coloured mineral inclusions.

Top: Striated topaz crystal with iridescence due to internal fractures. Bottom: Iridescence within incipient cleavage. Photos courtesy of Lily Faber, Gem-A.

If you've never thought about topaz jewellery, now's the time to add this colourful gemstone to your collection. London blue topaz especially is growing in popularity, with many jewellery lovers choosing this gemstone instead of aquamarine and sapphire for statement cocktail jewellery. 

Read more: What Should Be in the Ideal Gemmologist’s Toolkit?

Those born in November are lucky enough to have two beautiful gemstones as their birthstones. Find out more about citrine, a variety of quartz, here.

Learn more about gemmology with our Short Courses and Workshops.

Start your gemmology education no matter where you are in the world with our Online Distance Learning. 

Cover image: A trio of faceted topaz photographed by Pat Daly, Gem-A. 

Gem-A is thrilled to announce that Andrew Cody, founder of leading Australian opal company, Cody Opal, has been awarded an honorary FGA in recognition of his exceptional services to gemmology and the wider industry.

Cody was named the recipient of this special recognition at the annual Gem-A Conference 2017, which took place from November 4-5 in London. His achievements were honoured by Gem-A CEO Alan Hart, before he was invited on stage to accept and share his thoughts with Conference visitors and delegates.

Cody started collecting fossils, minerals and gemstones at just 12 years of age. He began cutting opal in 1964 after a school excursion to Coober Pedy, in northern South Australia, more than 800km north of Adelaide. In 1971, he established a wholesale opal and gem-cutting business, which expanded to include exporting to Europe, Japan and the United States.

Read more: Gem-A Conference Speaker in the Spotlight - Q&A with Adonia Pouroulis 

During his professional career, Cody has played a key role in transforming the reputation of opal as Australia’s National Gemstone. This included the production of an award-winning opal stamp series with Australia Post, the design of the official National Gemstone emblem and development of the official 'Opal Nomenclature'.

Cody is also a successful author, having written 'Australian Precious Opal – a Guide Book for Professionals'. In 2010, Cody and his brother Damian published a second book, 'The Opal Story', which is now available in six languages with more than 50,000 copies in circulation.

Cody is the joint founder and director of The National Opal Collection (NOC) with showrooms and museums in both Sydney and Melbourne. His opalised fossil collection is particularly impressive, and includes a 2.5 metre opalised pilosaur, and the opalised upper jaw of a rare Mesozoic mammal. This passion for collecting is accompanied by a strong business sense, leading to both of Cody’s businesses being awarded Government Export and Tourism Industry accolades. Additionally, he has a Gold Commendation from the Lord Mayor of Melbourne, is an honorary fellow of the Gemmological Association of Australia and is a research associate of The Australian Museum.

Read more: Gem-A Conference Speaker in the Spotlight - Q&A with Patrick Dreher

His commitment to the industry has seen Cody take on a number of official positions, including president of the Australian Gem Industry, founding member and chairman of the Australian Jewellery and Gemstone Industry Council, and president of the International Colored Gemstone Association.

Most recently, Cody has been working with a number of organisations on a review of opal classification. His goal is to create a universal system throughout the world gemstone community. In order to achieve this goal, he has put together 50 master reference sets for use in education and laboratories. These comprehensive sets contain 215 opal specimens in each.

When he’s not championing opals, writing, sourcing or working in the trade, Cody enjoys sharing his 50-year passion for opals at regular speaking engagements.

Cody commented: "When I was told of the nomination, I was overwhelmed and in fact I still am. I never considered myself deserving of this honour, and feel there would be many more that are better qualified! But it is with gratitude that I accept this important award from the world’s oldest gemmological institution.

Read more: Gem-A Conference Speaker in the Spotlight - Q&A with Samanta & Vladyslav Yavorskyy

"I am fortunate that my early interest in rocks and fossils grew into a hobby that also earned me a living throughout my life. It was about discovering treasure buried in the earth, outback adventures, travel and basically having fun. I loved being my own boss and, after all, who would employ me? So after all these years, I am still pursuing my hobby!

"The opal gemstone is amazing in that is has links to many areas of science; this has led to my collection of opalised fossils, pseudomorphs and related opal specimens from around the world."

He concludes with a spark of humour: "I don’t suppose you know anyone who wants to sell me a meteorite with opal, do you? I wonder if one day they will find evidence of bacteria preserved in opal on Mars?"

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 courtesy of Andrew Cody

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The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more

---

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more

---

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more

---

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more

---

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more

---

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more

---

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more

---

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more

---

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more

---

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more

---

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite).

It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special

Read more: Zircon from Vietnam

Admired since ancient times, turquoise is known for its beautifully unique colour, ranging from powdery blue to an unrivalled 'robin's egg' blue. Its colour and historic significance have resulted in turquoise becoming a favourite of many.

Displaying the different properties of turquoise: cut, clarity, colour and carat weight. Photos ©Gem-A

Gemmology of Turquoise

Gem turquoise is a polycrystalline copper material typically occurring in thin seams or small nodules. Turquoise is found in dry, barren, arid regions where copper, leached from rocks by rainwater, reacts with aluminium and phosphorus.

The result of this reaction is a porous, semi-translucent to opaque compound of hydrous copper aluminium phosphate with some evidence of iron. Copper produces the blue hues whilst chrome and iron add tonal variations of green.

Read more: Natural Vs Enhanced Lapidary Materials

Quite often, small patches or veins of brown or black host rock, known as matrix can be seen in the stone. The presence of these 'spider-web' patterns can often lower the value of the stone. However, some buyers actively seek stones with a presence of its matrix as they can be more unusual and attractive.

Turquoise simulant; paste. Photo courtesy of Pat Daly.

In terms of market-value, turquoise stones completely free from traces of matrix command a higher value, whilst those with evident spider-web patterns classified as desirable fetch second-place value in the trade.

The History of Turquoise

The earliest evidence we have of this gemstone dates to 3,000 BCE, under the reign of King Tutankhamun. The oldest turquoise mines are believed to have been located in the Sinai Peninsula of Egypt. Elaborate displays of turquoise were found on the gold jewellery of many Egyptian pharaohs, with the most extravagant found set on the iconic burial mask of King Tut himself.

Read more: Exploring the Varieties of Quartz

Ancient Persians believed that turquoise guaranteed protection. They adorned many of their palace domes with the sky-blue gemstone as it was said to represent heaven. Additionally, ancient Persians often engraved Arabic script into turquoise which would then be used to intricately decorate their daggers and horses' bridles.

Read more: Gem-A Confirms Oldest Known Carved Tourmaline

The highly prized 'robin's egg' blue - also known as 'Persian turquoise' - was venerated by the people of Persia (now known as Iran) as well as Siberia, Tibet, Turkey and Afghanistan. It was Turkish traders who later introduced this 'Persian blue' stone to Europe in the 13th century through the Silk Road.

Map of localities where turquoise is found throughout the world.

Archaeological evidence shows that not only was this gemstone used to embellish ancient Egyptian ornaments but was also a primary carving material for Chinese artisans. For many Native Americans, turquoise held great ceremonial value in being an instrument of exchange between tribes.

Read more: Understanding Red Beryl

As the national stone of Tibet, turquoise is enriched with ancient lore of being a symbol of good health, fortune and success. Often referred to as a token of protection, turquoise was commonly worn to ward off the presence of evil spirits, granting its wearer a sense of power.

Properties of Turquoise

The texture of turquoise is a direct result of its composition and structure. As an aggregate, polished turquoise with a smooth waxy lustre has a tightly-packed crystal structure, low porosity and a fine texture.

Read more: Getting to Grips with Multi-Tonal Gemstones

Turquoise gems displaying a dull lustre when polished have a coarser texture and increased porosity due to a less-dense internal crystal structure. This range in texture and porosity not only directly affects the overall appearance and lustre of this gemstone but also influences its durability.

Typically, turquoise is a fairly soft stone which made it a popular choice for talisman carving across ancient history. Throughout America, many carvers fashioned turquoise into amulets of Native American significance such as birds and animals.

Turquoise Jewellery Designs

With a hardness of 5 ½ - 6 on the Mohs scale and a fairly good toughness, turquoise is a suitable material for use of jewellery. However, the toughness of turquoise is significantly less in stones of a coarser texture.

This December birthstone is sensitive to direct sunlight and natural solvents such as perfume, oils and makeup products.

Read more: What Gemstones Are in the Beryl Family?

Due to its porosity, turquoise that is polished and faceted for commercial jewellery is often treated with paraffin compounds in order to increase its durability by oiling or waxing the surface of the stone.

Turquoise simulant; Dye-treated magnesite. Photo courtesy of Pat Daly.

Interested in finding out more about gemmology? Sign-up to one of Gem-A's Short Courses or Workshops. If you’re ready to get started, learn more about the Gemmology Foundation course.

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

Cover image: Surface patterns and textures of different cabochons of turquoise. All photos courtesy of Pat Daly at Gem-A.

With an opulent supply of rubies and pink sapphires, mining company Greenland Ruby is set to become an influential supplier of coloured gemstones. Here, International Women in Mining board member, Deborah Craig FGA DGA, shares her experiences in Greenland.

Greenlanders call the buried treasure of blood red rubies and vivid pink sapphires Aappaluttoq or "Big Red". Mining has now begun, positioning Greenland Ruby to become one of the market's most important suppliers of coloured gemstones. The rubies and sapphires will have an ethical pedigree that is increasingly important to buyers: responsibly-mined, with a transparent chain of custody and fully-disclosed treatments.

The new mine is also important to the people of Greenland, who voted for self-rule in 2008 with increased independence from Denmark. This means taking control of the development of their mineral resources and diversifying the economy from fishing and tourism, while creating self-sustaining tax revenues. Aappaluttoq is one of the first new industrial mines to come on-stream since this change went into effect.

Aappaluttoq is nestled between sea and glacier, 150 km south of the capital Nuuk, and east of the fishing village of Qeqertarsuatsiaat. The hilly, barren land is impassable, accessed only by small boat or helicopter (1). Geologists discovered significant ruby mineralisation in 2005; years of systematic exploration revealed the Fiskenaesset Anorthosite Complex. The metamorphic rocks that host the mineralisation are thought to be 2.9 billion years old, making Aappaluttoq one of the oldest coloured gemstone deposits worldwide.

1. The author and Jens Frederiksen, VP Security & Sales, Greenland Ruby. Helicopters are needed to reach the remote mine site.

A positive prefeasibility study was completed in 2011, after sufficient drilling and resource modelling. The ore is estimated to contain 10% corundum, of which 5% is gem quality, 20% near-gem quality (i.e. with inclusions), and 75% is commercial grade. The mine's profitability will depend on maintaining these robust grades, as well as efficiently extracting the gemstones from the ore.

Larger stones are found in the deposit, but their recovery is variable and difficult to predict. Therefore, only melee-sized rough material (<4mm) was included in the study and will underpin the steady sale of gemstones to the market. In this way, an industrial mine can provide a reliable supply of stones to jewellery manufacturers, something small alluvial operators cannot do.

Construction began in 2015 at a capital cost of US$25 million. Last fall, LNS Norway, parent company of Greenland Ruby, acquired the mine when previous owner True North Gems struggled to provide sufficient funding. LNS Norway has developed other projects in remote Polar Regions, including Antarctica and Svalbard. The mine is currently expected to operate for 9 years and produce 87 million carats of rough gemstones. Greenland Ruby is mapping and sampling its nearby Siggartartulik and Kigutilik projects, hoping to expand the mine's resource base.

The mine site will operate year-round and is staffed by Greenlanders flown to the camp for 2-3 week shifts. When possible, mine supplies are sourced locally, including fresh catches from local fisherman and hunters.

Aappaluttoq is a primary, hard rock deposit, containing two ore types: phlogopite hosts the higher chromium ruby, and leucogabbro hosts the pink sapphire (2). The ore is excavated from the open pit, mixed with lake water, and sent via conveyor belt on its circuitous route through the processing plant (3).

2. Aappaluttoq ruby in host rock.

A primary crusher reduces the size of the ore to below +60mm; a cone crusher reduces it further to below +20mm. After being washed, the crushed ore is mixed with a ferro-silicon solution (SG 2.7) in the dense media separation circuit and spun in a DMS cyclone. The heavy corundum sinks, and the lighter, floating waste material is diverted to tailings.

The corundum is separated into three size categories, before passing through a dry magnetic separator and an optical sorter. The optical sorter uses white light, a series of cameras, and a computer to identify red and pink crystals, triggering a pulse of pressurised air that separates the coloured material from the feed. The rough ruby and pink sapphire is transported from the processing plant to Nuuk, where any residual host rock is removed with hydrofluoric acid.

3. Aappaluttoq ore processing facility.

Greenland Ruby is currently calibrating its recovery process to reduce the amount of waste rock that makes its way through the system. This includes adjusting the conveyor belt speed so the optical sorter can work more effectively, and tweaking the hydrofluoric acid concentration and soak times.

The cleaned gemstones are sorted in Nuuk (4), against a customised master set of stones. First, the stones are divided into gem and near-gem qualities. Each of these qualities is then divided into four colour categories, ranging from deep red to intense pink to light lilac pink (5,6 & 7).

4. Holly Noahsen of Greenland Ruby sorts gemstones at the Nuuk office.

As noted by Christopher P. Smith, Andrew J. Fagan and Bryan Clark Craig in their article 'Ruby and Pink Sapphire from Aappaluttoq, Greenland' (The Journal of Gemmology, Volume 35/ No.4, 2016, pp.294-306), the stones have metamorphic-metasomatic type rubies and sapphires from other world deposits, including Montepuez.

They exhibit moderate to strong dichroism, have no visible colour-zoning, are are relatively high in chromium and iron and low in titanium, vanadium and gallium. Inclusions include clouds of minute rutile particles and some fine rutile needles, as well as arrowhead-shaped platelets.

Top left (5). Aappaluttoq ruby in matrix. Top right (6). Ruby crystal with triangular growth marks. Bottom (7). The sorters separate the stones by colour and clarity using a customised master set.

As Aappaluttoq is a primary deposit, the gemstones have been subjected to intense pressure and are most likely fractured. Removing the stones from their host rock is also difficult. This means that the majority of stones will need to be treated to improve their transparency, a process that also reduces their purple undertone. Treatments will be fully disclosed and the chain of custody will be carefully tracked. At present, Greenland Ruby will sell the treated rough material; the feasibility of bringing lapidary in-house is being examined.

Greenland Ruby has begun a soft launch of their rough rubies and sapphires. The company believes their strength lies in their ability to provide a steady supply of quality gemstones to jewellery manufacturers. Greenland Ruby is also considering strategic partnerships with select jewellery houses, to collaborate on marketing campaigns that will highlight the extraordinary provenance of Greenland rubies.

And the Greenland government and Greenland Ruby have the opportunity to develop an origin certification scheme, like the one that made Canadian diamonds a success story in a market increasingly looking for ethical sourcing alternatives.

Closer Insight

All that is red is not ruby on Greenland (8) - tugtupite, Greenlandic for "reindeer blood", is a silicate closely related to sodalite. Tugtupite is a much sought-after opaque to translucent, becoming redder in sunlight. Nuummite, meaning "from Nuuk", is a black opaque gemstone that exhibits iridescent flashes of colour due to its lamellar, fibrous structure (9).

8. Tugtupite in matrix: the gemstones becomes redder in sunlight.

Greenlandite (10) combines quartz and fuchsite to produce an opaque green stone that may be streaked with black schlieren or flecked with pyrite. Small scale miners extracting these stones have been supported by the Ministry of Mineral Resources with workshops on mining best practices, gemstone pricing and lapidary.

Left (9). Nuummite, only found near Nuuk. Right (10). Greenlandite with a schlieren vein.

The Ministry maintains an ongoing gemstone mapping project, compiling data from historical reports and noting when geologists and small-scale miners make interesting discoveries in the field.

Deborah Craig FGA DGA, would like to thank Greenland Ruby for sponsoring her field visit to Greenland.

All photos ©Deborah Craig, unless otherwise stated.

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: Iceberg in coastal waters. Image ©Deborah Craig

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The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more

---

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more

---

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more

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Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

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Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

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Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

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Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

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Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

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Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

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Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

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With its legends of gold seekers and treasure hunters, Arizona is still drawing the gaze of gemmologists and history enthusiasts to this day. Gem sculptor Helen Serras-Herman FGA takes us on a journey to this 'gold fever' state.

Living in a state where gold in abundance had been discovered in the nineteenth and early twentieth centuries, it was only inevitable that I would, at some point, find myself amidst gold fever.

Some incredible specimens of gold in quartz, found in central and southern Arizona, are part of splendid collections at the Arizona-Sonora Desert Museum as well as the University of Arizona (UA) Mineral Museum in Tucson.

A short time ago I finished carving two beautiful specimens of gold in quartz from an undisclosed location in southern Arizona, a commission work for the 'Arizona Lapidary & Gem Rough' store in Tucson. Today's gold miners are as secretive about locations as were the old timers.

Left: The stunning gold specimen from the Huachuca Mountains in Cochise County is part of the splendid mineral collection at the Arizona-Sonora Desert Museum in Tucson. Middle: This beautifully formed gold specimen from the Vulture Mine resides in the Arizona-Sonara Desert Museum's mineral collection in Tucson. Right: This is one of two beautiful specimens of gold in quartz from an undisclosed location in southern Arizona that I just finished carving.

My husband and I recently visited the Superstition Mountains, the centre of many gold legends and treasure hunts. We brought back some great specimens of gold in quartz from the famous Black Queen Mine in Goldfield.

But how did Arizona become a 'gold fever' state? I looked to prominent Arizona historian Jim Turner, a retired professor, author, and friend for some historic perspective: "In the 1730s, Spanish prospectors worked deposits twenty miles north of the US-Mexico border in an area later called Oro Blanco (white gold) because silver in the ore gave it a whitish colour." Later, when miners (the '49ers as they are known) started coming back from California's gold rush in 1849, they came through Arizona and found placer gold and gold in quartz deposits. Placer gold, found in stream bed deposits, originates from ancient larger ore deposits, from which small gold flakes detach and roll downstream.

Two great specimens of gold in quartz from the Black Queen Mine in Goldfield mined several years ago.

The Superstition Mountains and Their Legends

The Superstition Mountains are located less than an hour's drive east of Phoenix, just past Apache Junction. It is an area of 160,000 acres of dangerous land filled with saguaros, gold legends and Apache curses, conquistador and Mexican miners' stories, Jesuits' hidden gold treasure legends, as well as over 250 mysterious deaths. Gold seekers and treasure hunters have been searching in vain for the mine that bore the legend of the Superstition Mountains, the Lost Dutchman Mine, named after Jacob Waltz, a German prospector known as the 'Dutchman'. It is believed that he found the richest gold mine in the world, possibly an old Spanish mine, but took the secret to his grave in 1891, leaving behind only some riddle clues.

The legend of the Lost Dutchman Mine still reels in treasure hunters, who follow those clues on old paper or stone maps that take them deep into the Superstition Wilderness, an areas of 242 square miles that are filled with steep canyons, rocky outcroppings, cacti and thick brush.

Among the many that have lost their lives searching there, are three treasure hunters from Salt Lake City, Utah, lost forever as recent as July of 2010. The dangers from the Apaches, who killed many in the region protecting their sacred land and igniting the legendary Apache curse, are now long over. However, the danger from the summer temperatures that soar well above 110 degrees, are real, and make it deadly to unprepared hikers.

Mineral prospecting has been banned since 1983 when the area became a national wilderness, yet every year many travellers hope that they will stumble across the fabled gold mine.

Left: The Superstition Mountain & Lost Dutchman Museum treasure maps. Right: Dutchman matchbox SM Museum. Rich gold in quartz ore, supposedly from the Lost Dutchman Mine.

Lost Dutchman Museum

For a safe way to learn about gold in Arizona, its mining history and legends, head to the Superstition Mountain & Lost Dutchman Museum. With a variety of exhibits that allow the visitor to see what the Old West was really like, the museum provides a wealth of information about the old gold mines of the area. With stunning displays of treasure maps and over 40 books about the legend of the lost gold, many of them out-of-print, you truly understand the power of the legends and the quest for gold. After looking at the book display, one is very thankful that he museum offers and extensive bookshop!

The Superstition Mountain

The Superstition Mountain & Lost Dutchman Museum is located on Hwy 88, the historic Apache Trail, now designated as Arizona's first historic road. The trail covers 47 miles from Apache Junction to Roosevelt Lake. The drive, at times very rough with steep grades, offers some fantastic views of the backside of the Superstition Mountains, as well as of the three lakes that dam the Salt River: Canyon Lake, Apache Lake and Roosevelt Lake.

Nobody else can describe the Apache Trail better than president Theodore Roosevelt, on his way in 1911 to the Roosevelt Dam dedication ceremony: "The Apache Trail combines the grandeur of the Alps, the glory of the Rockies, the magnificence of the Grand Canyon and then adds as indefinable something that none of the others have, to me, it is most awe-inspiring and most sublimely beautiful".

Goldfield Ghost Town and Mine

Following the Apache Trail north for only a short drive, you will reach Goldfield Ghost Town, which lies in the shadow of the legendary Superstition Mountains. This is a true 1890's boomtown that had 50 working mines in the district after rich high grade ore was found in the area in 1892.

The abandoned town was revived in 1988, and today you can ride a narrow gauge railroad that circles the town for a mile and a half, offering a narrated scenic ride of the historic buildings and the famous Black Queen, Bulldog and Mammoth Mines.

Guided tours of the Goldfield Mine take you underground to a reconstructed mine very close to the original, now flooded mine.

Exploring Goldfield History

At the Goldfield Historic Museum, in the heart of the ghost town, you can learn more about the first very rich gold strike in 1892 and the 4,000 miners that lived there for five rich years. There are 13 treasure maps on display, from the so-called old Spanish maps, to more recent ones. A wonderful little museum with very friendly staff eager to share their knowledge!

Guided tours of the Goldfield Mine take you underground to a reconstructed mine very close to the original, now flooded, mine. It is always worth listening to the well-versed guides on the history of the local mine, discover the gold mining equipment that was moved there from the original nearby mines, and learn more about the mining procedures.

The Vulture Gold Mine

The Dutchman, Jacob Waltz, also prospected in the Vulture Mine, and was employed there as a consultant. The mine is located northwest from Phoenix near the old historic town of Wickenburg, famous today for its Western flair. There, in 1863 Austrian immigrant Henry Wickenburg, discovered gold. Legend has it that he was trying to retrieve a vulture that he had shot, when he found the quartz outcropping. Although Wickenburg sold the mine after a few years, it became one of the most productive gold mines in the history of Arizona, producing gold worth more than 200 million dollars. The gold is embedded in the quartz ore, and requires hard rock mining. President Franklin Roosevelt closed the mine in 1942, during World War II. The miners left, believing they would return in 6 months, but the mine never re-opened.

The Vulture mine used to be open daily for self-guided tours when we last visited in 2011, but now it is accessible only via a two hour guided walking mine tour on Saturday morning 8:30-10:30am. It is a great place to visit and walk the trails that take you by the 'Glory Hole', the Blacksmith's Shop and the Main Shaft, the Assay Office, and the 80-Stamp Mill. At the Power Plant, which served as the Machine shop, time almost stood still. All the equipment is still there, just a bit dusty and rusty, waiting for miners. This is a rarely seen sight, eerie and awe-inspiring. All the tools are left in place, as if the workers are just out for lunch.

Goldfield as it is today.

Prospecting for Gold Today in Arizona

According to stats from Gold Maps Online^TM their maps show currently 46,199 active gold claims and 364,629 abandoned claims in the state of Arizona on public lands.

A great resource for information about gold in Arizona is the 'Gold Prospecting' page of the Arizona Geological Survey's (AZGS) website.

Gold in quartz from the Black Queen Mine. This site was one of three major mines; along with the Bulldog and Mammoth Mine that made Goldfield famous in the 1890s.

Several associations in Arizona promote recreational gold planning and mining. Members of the Arizona Association of Gold Prospectors (AAGP) Phoenix Chapter usually go prospecting within one or two hours' drive from Phoenix, Mesa or Tucson. The Gold Prospectors Association of America (GPAA) is a national organization. With five chapters in Arizona, there are plenty of locations and options to follow your gold fever.

For a two hour gold panning adventure join Apache Trail Tours, an award-winning our company based in Goldfield Ghost Town offering guided tours from one to eight hours.

If by now, you are sweltering from gold fever, besides going prospecting with any of the local gold clubs or purchasing gold specimens, you can buy your own gold mine in Arizona. My husband is already checking his wallet!

Next time you visit Arizona, please take a trip to these wonderful historic sites, museums and mines; they will enhance your knowledge about the difficulties of gold hard rock mining, the thrill of placer gold panning, as well as the successes and failures of gold-seeking. You may be inspired to go gold prospecting, or simply enjoy all the legends disseminated for over a century.

Sources

For currently available claims, please visit: goldmapsonline.com/arizona-gold-map.html, azgs.az.gov/minerals_gold.shtml, arizonagoldprospectors.org, goldprospectors.org, apachetrailtours.com, goldrushexpeditions.com/state/arizona/.

All images courtesy of Helen Serras-Herman.

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 Goldfield Ghost is an abandoned town, revived in 1988, filled with museums, shops, and an underground mine, all in authentic-looking buildings. Image ©Helen Serras-Herman.

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The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more

---

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more

---

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more

---

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more

---

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

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Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more

---

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more

---

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more

---

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

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Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

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Cally Oldershaw FGA DGA describes the thrill of finding agate on the shores of Cornwall and reveals how these subtly-toned gemstones are shaping her jewellery collections in collaboration with geologist and lapidarist, Ben Church.

With many more people choosing to stay in the UK for their 'staycations' rather than going abroad for the holidays, the numbers visiting popular tourist regions such as Cornwall is increasing.

Agates of Cornwall

Of the Cornish rocks and the many millions of pebbles on the beaches, only a few are true agates showing the characteristic banding that defines them. The process of looking for agates is simply to visit a beach and walk slowly, looking at as many pebbles as possible. Determining whether a pebble is an agate is more of a challenge, it takes time and experience to identify the agates and from those, the ones that will be best suited to be made into jewellery.

A selection of Cornish cabochons and slices from Cally's jewellery collections.

Time and location are also important. The best time to look for the agates is when the tide is going out, as the banding in the agates shows better when they are wet; searching the intertidal areas from the high tide 'strand line' is likely to be most successful. Some beaches yield more agates than others and this changes with the tides and the seasons as the amount of sand and pebbles on each beach fluctuates, sometimes daily, throughout the year. It took us almost two years of researching and visiting potential collecting sites to develop an effective method of finding Cornish agates.

What is Agate?

Agates are a type of quartz, the same family as colourless rock crystal, purple amethyst, grey to brownish-grey smoky quartz, black morion and yellow citrine crystals. Cornish agate consists of banded varieties of chalcedony and many occasionally include areas of crystalline amethyst, rock crystal or morion. Chalcedony is defined as microcrystalline or cryptocrystalline (hidden crystals) quartz, where crystals are too small to be seen without using a microscope.

No two agates are alike; each is formed over millions of years and has its own unique colours and patterns. Their distinctive colours include grey, cream, caramel, white, colourless chalcedony. Some pieces have translucent or transparent bands, where it is possible see through the agate.

Left: A model wearing a pendant made of Cornish agate. Right: A Sculptural piece approx. 10cm across with purple crystalline amethyst

The Cornish agate pebbles and polished pebbles have been used in crystal therapies. Named for their colours; the more vibrant poldark agate and Cornish caramel agate, are believed to help energise, while the cooler colour of Cornish grey agate and Cornish cream agate have a calming effect. A reddish coloured blush agate is particularly rare.

Cornish Agate Formation

Most agates have a volcanic origin, with the agate filling cavities or vesicles (small bubbles) within volcanic igneous rocks. Cornish agates formed about 240 million years ago and have a different origin. The characteristic granite landscape of the Southwest of England including Dartmoor, Exmoor, and Bodmin Moor, as well as the Scilly Isles, are all part of a large intrusion of igneous rock, which slowly cooled between 1.5 and 3 miles underground, causing fissures and cracks in the surrounding rocks (country rocks).

Cornish agates formed from got silica-rich fluids that filled these cracks and fissures called veins (like the veins within a leaf) within the country rocks, and then cooled and solidified to form vein agate.

Another selection of Cornish agate jewellery in a variety of colours.

The country rocks surrounding the granite were folded and faulted as the sea floor between Cornwall and Europe was compressed, and the rocks buckled up to form the landscapes and coastal cliffs of Cornwall. Over millions of years, these folded and faulted rocks were weathered and eroded. In rare cases, the veins can be seen in the rock faces and cliffs at the back of beaches. As the rock was broken down, agates were released to the beaches, where the energy of the seas moved the agate back and forth with the tides, gradually grinding sharp angular rock fragments into smooth rounded pebbles.

Cornish Agate Jewellery

Having collected and sorted the agates, the first step in making the jewellery is to make a slice to check the pattern within. Ben [Church] uses a saw with a 25cm diameter diamond blade, which cuts about 10cm an hour. The blade is lubricated and cooled with honing oil that gives a smooth satin surface and is wonderfully tactile. It can take several hours to prepare and make the first cut through one of the larger pebbles.

We assess each slice individually, inspired by the unique pattern of each agate, to decide whether to trim and polish a slice as an irregular shape (freedom form), or draw around set templates to produce oval and teardrop shapes for example. We then sort the slices to choose which will be made into cabochons, with a rounded upper surface, and which will be worked as polished, flat slices.

Left: Cally collecting Cornish agates. Right: Cornish grey agate slice on chord.

Initially the flat slices were made into freedom forms with a drilled hole so that agate slice could be worn on a leather cord. A later development was a surf board design with further accentuated the Cornish essence of the agate, fitting with the Cornish beach and surfing lifestyle.

Adding a sterling silver pinch ball and chain was the next development phase. This jewellery has Made in Cornwall accreditation, as we collect the Cornish agates from the north coast of Cornwall, as well as cutting, slicing, polishing, drilling and packaging the jewellery all within about 10 miles of where they have been found. Pieces have been exhibited at Made in Cornwall events and displayed in the Lander Gallery in Truro, Cornwall.

This year we also had some of the agates mounted in sterling silver bezels and displayed on sterling silver necklaces to enhance the natural beauty of the agates, whilst placing the agate in the content of fine jewellery.

The Infinite Wave Jewellery Collection

The latest range of jewellery is our Infinite Wave Cornish Agate Collection. We have used the waves of the Cornish coastline as our inspiration to design unique luxury pieces.

Left: Cornish caramel and Cornish cream agate polished pebble. Right: A model wears jewellery design featuring Cornish agate

Having worked with gemstones and with the jewellery industry for more than 30 years, it has been a wonderful challenge and an exciting experience to bring together my love of gemstones and jewellery to design something so uniquely Cornish.

My vision for jewellery, as a consultant in sustainable mining and ethically sourced gemstones, is to design a collection that, in collaboration with jewellers' worldwide, would be produced using only Fair-mined and Fairtrade gold and platinum, and ethically sourced silver.

Find out more at cornishagates.co.uk

This article originally appeared in the Winter 2017 (Vol. 26 No.4) issue of Gems&Jewellery magazine. 

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: Cornish grey agate slice © Ben Church. All images © Ben Church.

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The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more

---

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more

---

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more

---

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more

---

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more

---

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more

---

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more

---

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more

---

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more

---

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more

---

Deborah Mazza FGA explores how contemporary gem carvers are continuing an age-old artistic tradition of storytelling through gemstones.

Once upon a time, in a land far, far away, there was...How often have we all heard these words? This is the most common beginning to a story that fires the imagination, transporting one into a magical world full of marvels and wonders, starting in our childhood and possibly continuing into adulthood. But, what has this to do with gemmology and gemstones? Well, let me tell you my story starting in Idar-Oberstein, a little town in Germany, where gem carvers continue to tell stories through stones, carrying on an old tradition that started in ancient times. Any good story has interesting characters, here are mine...

Erwin Pauly

In his little workshop in Veitsrodt (Idar-Oberstein), surrounded by nature, Erwin Pauly creates objects of beauty and is in very high demand by VIP's worldwide. He learned the art of gemstones carving from masters of the time and has now become a master carver in his own right. Erwin Pauly is generous in giving his insight and helping aspiring artists who want to learn from him, he trained his three sons who have now acquired their own worldwide fame, one of them in Hand-Ulrich Pauly whose works can be admired in Tucson.

Example cameos preformed from gemstones. Far left is a citrine preform by Bernd Munsteiner, worked as a cameo by Erwin. Note the use of Munsteiner's lines and circles in Erwin's creation. He uses the line as a divider between face and hair, working it to then develop in a wheat sheaf. The circles are then part of the hairstyle. Image credits Erwin Pauly.

Mr Pauly started out with traditional agate carvings, consisting of an oval cameo on layered agate with classical motifs, or head portraits either shown in profile or front view. These portraits are also of living people, and can now be admired in his studio or in the museums of Idar-Oberstein.

Erwin Pauly thinks of himself as an artist who speaks through gems. He wanted to break away from the classical oval carvings to tell his own stories, so he started introducing other cameo shapes. In some of these carvings the face or the hair breaks out of the confinement of the frame bringing a new contemporary quality to the piece and adding another essential part to the story. He also started using other gemstones for his creations, opal, ametrine, citrine, beryl, rock crystal, and collaborates with Bernd Munsteiner for some of his pieces.

Munsteiner

Munsteiner has become a very well-known name in the trade. At shows everyone rushes to visit the Munsteiner booth and admire the latest creations this workshop produces. Munsteiner's introduced something new to the trade; inspired by nature, they challenged conformity and tradition, embracing the inherent inclusions and irregularities in gemstones, which unleashed a wave of creativity in many new artists. Their understanding and feeling for gemstones seems to continue exactly where nature left off. Munsteiner is made up of Bernd Munsteiner, his son Tom, and Tom's wife Jutta who is a very talented jeweller and channels the mood set by the lapidary artist into individual jewellery pieces. The final designs that emerge from Munsteiner's gemstone sculptures remind one a little of the Bauhaus movement and minimalism due to the simply, unfussy lines in pieces. But there is much more behind these pieces than what meets the eye.

'Magic Eye', Brooch with a 43.95 ct citrine, agate and diamond in 18 ct yellow gold. Image credit Munsteiner.

Munsteiner uses the optic laws of refraction and reflection to produce interesting three-dimensional effects in pieces; highlighting that the essence of a crystal can be sft and organic, not just angular and hard. Munsteiner believes that nothing is more powerful than an idea, and sometimes this idea has to wait until the right gemstone, with the right set of inclusion in the right arrangement, comes along. Only then will it be able to tell us a story.

Bernd, Jutta and Tom Munsteiner. Image credit Munsteiner.

Herbert Klein

Nothing really prepares you for the surprise you feel when presented with this company's miniature creations, including leaves, flowers, blossoms, fish and mammals all carved out of various gemstones. The attention to detail is stunning, the cuteness of some almost unbearable. All these little creations, some no larger than a one Euro coin, appear to have a life of their own and tell a story, all with a certain sense of humour.

Carved animal creations with a stunning amount of detail engraved. Image credit D.Mazza.

The current artist-carver at Herbert Klein is Stefan Klein, who started as an engraver in his father's company and developed his skills. Stefan's creative process is long, leading to a perfect creation; he carefully studies pictures and films of the nature he intends to represent in his pieces, he establishes a connection with the piece until he declares it finished and only then reveals its fairy tale.

The smallest tourmaline frog, placed on a one Euro coin for scale. Image credit D.Mazza.

None of his pieces are exactly the same. They all have small differences, whether that is the materials used, the inclusions within or the representation chosen. Each aspect contributes to telling a fantastic tale.

Stefan Klein in his workshop. Image credit D.Mazza.

Conclusion

There are many more stories and tales I can tell you about these artists and their creations: Patrick Dreher, for example, creates stunning gemstone animal sculptures that seem to come to life as they give the effect of muscles rippling beneath the skin. Michael Peuster creates stories out of different materials, gemstones and elements put together, while Manfred Wild sees a single, lonely stone in a gem parcel, picks it up and creates a story around what he sees.

But these are all stories for another day.

To find out more please visit: erwin-pauly.com, munsteiner-cut.de and herbert-klein.de.

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 Erwin working in his workshop in Veitsrodt. Image courtesy of D. Mazza.

---

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more

---

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more

---

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more

---

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more

---

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more

---

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more

---

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more

---

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more

---

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more

---

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more

---

Sarah Steele FGA DGA, visits a growing community of gem cutters in Newcastle who are quietly, but effectively, pushing boundaries.

When we think about the great gem centres of the world, Newcastle in the North East of England wouldn't necessarily spring to mind. There is however a growing community of gem cutters who are challenging our perception of the faceting industry, entering and doing extremely well in international competitions, and quietly cutting world class gems for both pleasure and profit.

The NE1 Faceters (a play on words standing for 'Anyone Faceters') was established in 2012 by Steve Smith and Paul Sampson. As members of the UK Faceters Guild, both were keen to pass on their knowledge to a younger generation so Steve, along with Paul a master goldsmith and keen faceter himself, decided to form a group open to promote the art of faceting within the UK.

The pavilion girdles of Sarah's synthetic Verneuil ruby unfortunately showing a textbook example of chatter marks.

The group is run on a not-for-profit basis but has within its membership a number of professional cutters. The membership has an age range from 11 to 87 from diverse backgrounds, many of them scientists or engineers as well as archaeologists and artists within the ranks. The group meets monthly to broaden their knowledge of gemmology, but they also run annual summer schools where members and visitors spend a weekend cutting together under supervision of Paul and Steve. For the past four summers, I have packed up my faceting machine and joined them for the weekend. As a gemmologist I believe that the best way to truly understand a gem species is to cut it yourself.

In June, I visited the Saint Marie Aux Mines Mineral Show and had purchased a half boule of synthetic Verneuil corundum for a mere €20. I was keen to see if I could cut a large stone at this year's faceting school. I have pre-formed the ruby back in my workshop so it was ready to drop on arrival in Newcastle.

As I cut the girdle of my stone I'm feeling rather smug, the clarity is good and there is no obvious colour zoning. As I move on to the pavilion facets, however, I notice a distinct difference in the feel of the stone on the diamond lap in two cutting plains. The design is an antique cushion square and two sides of the pavilion are beginning to look a different texture to those on the opposing sides. I change to a finer grit lap to begin with pre-polishing but the problem seems to be getting worse. Rather than polishing the problematic facets, chatter marks are appearing in increasing quantity. Steve advises me to touch the stone on the lap in only three spots rather than the fluid arc movement we would normally use. This can often cure this problem as the diamond is now only cutting in three distinctive planes. In the case of this stone however, the problem persisted.

Steve then asked me how I'd aligned the rough on the dopstick. I had assumed that the C-axis on a Verneuil boule was parallel to the longest axis. Rather embarrassingly I was then informed that the C-axis in the Verneuil product always lies within the plane along which the boule is split, though not necessarily parallel to the boule's length, so I'm probably polishing along at least one cleavage direction.

The only hope for this stone is to realign the table at a slight angle, re-dop and recut the pavilion. I decide to leave this for a later date and cut an amethyst aligned at the correct angle previously prepared by Steve. Mine isn't the only setback over the weekend, we have chipped culets, stone knocked off the dop (everyone's worst nightmare), extra facets, missing facets, facets cut on the wrong cog, poor polish, no polish - the list is endless.

Simone Muehlbayer receiving expert tuition from Steve Smith.

Paul and Steve offer one-to-one tuition over the weekend. Simone Muehlbayer has been allocated to Steve and is an amateur jeweller keen to cut her first stone. By Saturday evening she was very proud of her polished pavilion and girdle. Conversation at Saturday evening's annual barbeque revolves around the problems associated with faceting from a British perspective. Surprisingly, the major problem lies in the acquisition of the faceting machines themselves.

There are over a dozen of us participating over the weekend and no two machines are identical. Five of the machines are the GemMaster11 fac-Ette, a machine considered by many to be the Rolls Royce of faceting rigs. However, this machine has not been in production for many years. I imported my second hand machine from California four years ago which including duty was in excess of £4,000. The rights to the GemMaster 11 machine were purchased by Wyatt Yeager, a diamond prospector and fan of the machine. I spoke to him regarding his plans for future production and he told me that the costs are so prohibitive that he intends to manufacture to order only. A new machine is likely to retail at $6,000 and that is working on a tiny profit margin.

Steve tells me that in his opinion, many of the cheaper faceting machines on the market are simply not good enough quality to cut a stone to the exacting requirements required for competition and high end clients. As a result, many members with engineering expertise heavily modify their own machines, some members choosing to build from scratch. Steve and Paul are seriously considering producing and retailing a British machine but it is difficult to find the precision engineering companies at a cost that would be feasible. In the meantime, Steve and Paul manufacture their own metallic resin and soft type-metal laps which are machined perfectly flat. They also mix their own custom recipe diamond compounds specific to the gem species they are polishing.

Simone Muehlbayer's brilliant cut citrine, featuring a feather in the girdle duplicated many times when viewed through the table.

By Sunday evening Simone has produced a fantastic brilliant-cut citrine that Steve confirms to be considerably better than a commercial cut stone. Unfortunately, a feather in the pavilion is giving an interesting fingerprint look when viewed through the table but she is rightly proud of her achievement. I don't leave with the 20 ct ruby I'd hoped for but I am happy with my modified emerald-cut amethyst and as usual have learnt a vast amount about cutting.

The NE1 Faceters can be contacted at nei1info@btinternet.com to discuss cutting projects and any unused faceting machines would be gratefully received.

All images courtesy of Sarah Steele.

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 of Gemma McFarlane, Sarah Steele and Nigel Wilson cutting on their respective machines. Image: ©Sarah Steele

---

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more

---

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more

---

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more

---

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more

---

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more

---

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more

---

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more

---

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more

---

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more

---

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more

---

First published in The Journal of Gemmology Vol.35/No.8, Robin Hansen FGA, gem curator at the Natural History Museum, London, takes us through the gemmological, mineralogical and historical background of two fascinating cameos from the late 1800s.

The collections of the Natural History Museum (NHM) in London include minerals, gemstones, worked objects and carvings. I recently had the pleasure to study two chalcedony/agate cameos that were fascinating for their gemmological, mineralogical and historical interest. What made both so delightful was that they had been carved onto the exterior of geodes. Both were purchased from gem carver Wilhelm Schmidt by the Geological Museum of the British Geological Survey in the late 1800s; the specimens then became part of the NHM collection in 1985.

Wilhelm Schmidt (1845-1938) was born in Idar (now part of Idar-Oberstein, Germany). At the age of 15 he was sent to Paris as an apprentice to learn the craft of gem engraving, under the masterful eye of cameo cutter Arsène. He was trained in the neo-classical style, but stone cameos were going out of fashion when he graduated in the 1860s.

Although Romanticism brought in new trends of Renaissance subjects for cameos, Schmidt's interest waned and he returned to Germany. Following the Franco-Prussia War in 1870 and subsequent events, Wilhelm moved to England with his brother Louis, where he changed his name to William.

The brothers set up a business in Hatton Garden that ran from 1872 to 1915 (Seidmann, 1988). During this time William regularly sold cameos, intaglios and carvings to the Geological Museum. His work was of interest because he utilised more unusual materials such as labradorite, moonstone and opal.

Figure 2. This cameo, also by Wilhelm Schmidt, depicts the head of Jupiter and is carved on the exterior of an agate geode. Specimen BM.1985,M16225; courtesy of NHM London © The Trustees of the Natural History Museum, London.

Of the two cameos documented here, the first specimen is BM.1985,MI5547, described in the museum's handwritten register as 'Cameo in Agate-Jasper on Amethyst' (see cover image). Depicting a Roman man with a wreath on his head, Schmidt carved the layer just beneath the amethyst druse, which consisted of pale orangey pink chalcedony containing fine crisscrossing dark veinlets and a few thin linear arrays of red iron-oxide spots. The layer of chalcedony continues into the background of the carving, giving a halo effect. The amethyst creates a simple dark backdrop, and it is a surprise to most viewers to find the centimetre-sized amethyst crystals on the back-side of the piece.

The terminations of many of the crystals have been ground away, presumably to give the cameo a more even surface. The object measures 78 x 66 x 38mm and was purchased from W. Schmidt on 23 December 1886 for £8. Although no location is given for the source of the raw material, it is likely to have been Rio Grande do Sul in Brazil, well known for its amethyst, agate and jasper, as well as its connections with Idar-Oberstein in the 1800s.

The second cameo, BM.1985,MI6225, is described in the museum's register as 'Head of Jupiter (after the antique) cut on the exterior of a hollow Agate from Oberstein' (Figures 2&3). It is carved as the head of the Roman god Jupiter, with long flowing hair and beard. The agate is very pale purple to light beige and locally contains small, dark, translucent, angular areas. It also has very fine red veinlets and tiny spots with an iron-oxide appearance.

Figure 3. The same cameo by Wilhelm Schmidt showing the rear interior lined by quartz crystals. The raw material originated from Idar-Oberstein, Germany. Image courtesy of NHM London, © The Trustees of the Natural History Museum, London.

On the rear, a fine layering of the agate can be seen around the edges of a hollow geode lined by a druse of sparkling quartz crystals up to 3mm in size that range from colourless to an ever-so-slight hint of pale amethyst. The carving measures 55 x 38 x 27mm and was purchased by the Geological Museum on 25 March 1891 for £10.

Roman figures were a common theme for Schmidt, and the NHM collection includes other cameos that he carved with the head of Mars, several of Minerva and Julius Caesar and a bust of Britannicus.

Reference: Seidmann G., 1988. Wilhelm Schmidt: The last neo-classical gem-engraver. Apollo, No. 317, 12-16.

To find out more about the collections visit nhm.ac.uk.

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 and figure 1: In the late 1800s, Wilhelm Schmidt carved this cameo of a Roman figure into chalcedony adjacent to amethyst crystals that originally formed part of a geode. This composite image shows four sides of the object. Specimen BM.1985,M15547, courtesy of NHM London, © The Trustees of the National History Museum, London.

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The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more

---

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more

---

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more

---

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more

---

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more

---

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more

---

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more

---

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more

---

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more

---

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more

---

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