Birthstone Guide: Peridot for Those Born in August

Lily Faber FGA, gemmology and diamond tutor at Gem-A unveils the striking tones of peridot, the August birthstone; a fitting beauty of nature to compliment the vibrant and zesty 2017 Pantone Colour of the year, 'Greenery'.

Peridot is the birthstone for August and is known for its rich, green colour. It is one of the few gems that comes in only one colour (green), and its name is thought to come from the Arabic word ‘faridot’ which translates to ‘gem'.

Peridot is a transparent gem variety of olivine. Coloured by iron, it comes in a range of greens from yellowy-green to brownish-green. It also has a slightly oily or greasy lustre, but don’t let that description put you off!

With its distinct olive-green hue that is the embodiment of long, summer days, some believe that peridot can bring happiness, luck and prosperity while calming anger, conquering fear and protecting one from evil spirits.

Read more: Pantone Colour of the Year points to Peridot in 2017.

Formed in the earth’s mantle, this gem makes its way to the surface via volcanic eruptions and is found in ancient lava beds. Occasionally, it can also come from outer space! A special type of meteorite called a pallasite meteorite sometimes contains peridot within its iron-nickel matrix. If you slice the meteorite open, it will reveal a smattering of transparent to translucent gems.

Zabargad Island, (St. John’s Island) in the Red Sea off the coast of Egypt, is believed to be the earliest known source for peridot. Centuries ago, the Greeks called this island Topazios, which was also their name for peridot. Later, this island was mined for peridot to fill the coffers of Egyptian kings and anyone who tried to set foot on the island at that time was threatened with death.

It has been said that many of Cleopatra’s emeralds, a favourite gem of hers, were actually peridot. Strangely, the ancient Romans called peridot the ‘Evening Emerald’ because they believed that its bright green colour could only be seen at night, which is clearly not the case!

Read more: Field Trip: Exploring the Wonders of Myanmar.

Other localities include Myanmar, Pakistan and the Peridot Mesa in the San Carlos Apache Native American Reservation in Arizona, USA.

This is a brittle stone with a hardness of 6 ½, which leaves it vulnerable to chips and scratches. Care should be taken when set in jewellery, especially rings. Perfumes, hairspray and make-up can also damage the stone, so spritz your perfume prior to draping yourself in peridots.

Common inclusions are lily pads, which consist of crystals, typically chromite, and are surrounded by curved stress cracks. Mica flakes can sometimes give a brownish tinge to the gem, and needle-like ludwigite inclusions are also seen.


Lilypad inclusions. Image by Pat Daly FGA, Gem-A.


Mica inclusions. Image by Pat Daly FGA, Gem-A.


Ludwigite and vonsenite inclusions. Image by Pat Daly FGA, Gem-A.

A characteristic feature that can help differentiate peridot from emeralds is its high birefringence of 0.036, within an RI range of 1.65 to 1.69. This causes the effect of doubling of the inclusions and facet edges. You can often see this doubling with a loupe or even with the unaided eye if the stone is big enough.


Doubling of inclusions and facet edges observed peridot (note: this image is not out of focus). Image by Pat Daly FGA, Gem-A.

The most prized peridots are those of larger size, with a rich, ‘oily’ green colour and few inclusions.

Read more: Ruby for Those Born in July

While this stone has gone in and out of fashion over the years, I encourage you to think of peridot for your next piece of jewellery not only for its gorgeous colour, but also for its interesting and varied history.

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 Peridot ©GemA.


Don't Miss the Summer 2019 Issue of Gems&Jewellery!

Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online. 

Read more


Breaking down the Misunderstandings about Precious Coral

Breaking down the Misunderstandings about Precious Coral

Inspired by Pantone’s ‘Color of the Year 2019’, Rui Galopim de Carvalho FGA DGA dives into the underwater world of precious coral and addresses some of the misunderstandings around its use in the jewellery industry.

Read more


 

Additional Info

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Rio Tinto Reveals The 2.11ct Argyle Everglow Red Diamond

It is always an exciting time of year when Rio Tinto unveils what has been discovered at its Argyle diamond mine. Typically, this is beautiful pink diamonds, with the occasional purplish violet tones. Even rarer still are the fancy red diamonds, which remain a mysterious quantity even today. 

It is without doubt that red diamonds are some of the most beautiful and captivating gemstones, largely due to their extreme rarity. In fact, it has been estimated that as few as 30% of all red diamonds have been discovered, leaving many curious to what showstoppers remain untouched below the surface.

The colour red is thought to symbolise love, passion and strength, which makes red diamonds an especially meaningful shade for collectors with significant funds. Those with an eye on the market will undoubtedly have spotted The Argyle Everglow - a 2.11 carat polished radiant-cut diamond presented as part of the 2017 Argyle Pink Diamonds Tender. 

Read more: The World's Most Expensive Diamond at Auction.

The Argyle Everglow was immediately identified for its miraculous size, colour and clarity and, after being assessed by the Gemological Institute of America (GIA), it has been given a grade of Fancy Red VS2.

Just to put the significance of this into perspective, in the 22-year history of the Argyle Pink Diamonds Tender, there have been less than 20 carats of fancy red certified diamonds sold.  

Argyle Everglow 2.11 carat radiant shaped Fancy Red. Image by Rio Tinto.

The 2017 Argyle Pink Diamonds Tender, also named 'Custodians of Rare Beauty' will present 58 diamonds with a total carat weight of 49.39 carats, including four fancy red diamonds, four purplish red diamonds, two violet diamonds, and one blue diamond.

The five 'hero' diamonds in the collection are as follows:

  • The Argyle Everglow, 2.11 carat radiant shaped fancy red diamond
  • The Argyle Isla, 1.14 carat radiant shaped fancy red diamond
  • The Argyle Avaline, 2.42 carat cushion shaped fancy purple-pink diamond
  • The Argyle Kalina, 1.50 carat oval shaped fancy deep pink diamond
  • Argyle Liberté, 0.91 carat radiant shaped fancy deep grey-violet diamond

 

Argyle Avaline 2.42 carat cushion shaped fancy purple pink. Image by Rio Tinto.

Read more: 'Diamonds: Rare Brilliance' Showcase Collection.

Found primarily in Australia, Africa and Brazil, red diamonds are so rare that only 20 to 30 stones are officially known to exist with each one measuring less than half a carat on average.

Argyle Liberte 0.91 carat radiant shaped fancy deep gray violet. Image by Rio Tinto.

Argyle Kalina 1.50 carat oval shaped fancy deep pink. Image by Rio Tinto.

In light of the reveal of The Argyle Everglow, we hit the archives to recall the most spectacular discoveries of red diamonds that have captured the interest of high-end jewellers, aficionados and collectors worldwide...

The Hancock Red Diamond

Whilst this round brilliant-cut diamond is not famous for its size, weighing in at 0.95ct, it is praised for its astounding deep red and purple colours, making it one of the most highly sought-after stones to date.

The Kazanjian Red

With a history nearly as big as its size, this South African diamond, although later cut in the Netherlands, was found over 100 years ago weighing in at 5.05 carats from the original rough 35ct stone. In 2010, the Kazanjian red diamond was on display in the Morgan Memorial Hall of Gems at the American Museum of Natural History before being purchased by Kazanjian Bros. Inc.

The Moussaieff Red Diamond

Discovered by a Brazilian farmer in the 1990s, the Moussaieff Red, otherwise known as 'Red Shield' is an internally flawless, triangular brilliant-cut fancy diamond famous for its 5.11 carat weight. This iconic diamond remains one of the largest red diamond discoveries in the world to date.

The Edcora Red

This pear-cut fancy red brown diamond, weighing in at 5.71 carats is known as the 'lost stone' due to vanishing from the public eye into the collection of a private investor. Whilst there have been no identified photographs of this red diamond, its existence has been well-documented in writing.

The DeYoung Red Diamond

The DeYoung red diamond is a rare 5.03 carat unmounted diamond purchased by a Boston jewellery seller at a flea market. Sydney DeYoung initially mistook the stone for a garnet but, upon noticing its high quality, had it laboratory tested to reveal its true identity as a red diamond. After his death in 1986, the DeYoung red diamond was given to the Smithsonian Institution’s Natural Gem and Mineral Collection where it remains on public display.   

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 2017 Argyle Pink Diamonds Tender hero diamonds from Rio Tintos Argyle Diamond mine. ©Rio Tinto.


Don't Miss the Summer 2019 Issue of Gems&Jewellery!

Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online. 

Read more


Breaking down the Misunderstandings about Precious Coral

Breaking down the Misunderstandings about Precious Coral

Inspired by Pantone’s ‘Color of the Year 2019’, Rui Galopim de Carvalho FGA DGA dives into the underwater world of precious coral and addresses some of the misunderstandings around its use in the jewellery industry.

Read more


Additional Info

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Fossicking in the Outback

Carmen Garcia-Carballido FGA DGA L.Geology MSc. EurGeol travelled to the southern hemisphere to find out more about the opals and sapphires of eastern Australia.

To test the skills acquired in two years training as a gemmologist with Gem-A, my husband planned a three week field trip to the sapphire and opal fields of eastern Australia.

We flew from Aberdeen to Sydney, hired a motorhome and headed into the outback of New South Wales (NSW) and Queensland. However, cyclone Debbie making landfall on the coast put paid to our plan to visit a gem dealer in Yepoon and check out the Marlborough Chrysoprase. To keep safe we stayed inland, driving 4,500 km in 13 days and camping at a different site every night.

Map of Australia showing key sapphire and opal locations and the field trip itinery. Image by Peter Scott-Wilson.

Two days from Sydney, our first gem field was Glenn Innes where we tried fossicking for the first time. A petrol station sold us a ‘bucket of dirt’ and rented sieves for AUS $20. Washing the dirt off, we found our first sapphires and zircons. We admired Robert Cook's collection of locally mined parti-colour sapphires that he cuts in his shop at the Visitor Information Centre. After some purchases, my husband had to drag me out of Robert’s shop.

60 km west at Inverell, we met Jack Wilson, who owns a longstanding sapphire mine and his wife Dallas, who designs lovely jewellery with blue sapphires from his mine. I bought some untreated rough blue sapphires with the idea of learning to cut them myself. Jack explained the host rock (i.e. the primary deposit where the sapphires formed) has not been identified. These sapphires are found in secondary, alluvial deposits.


Rough untreated sapphires from Jack Wilson's mine. L-R 10.21 ct and 6.54 ct.

After a long drive west, roads littered with dead kangaroos took us to Lightening Ridge, famous for its black opals. The town in the desert appeared empty. Tourists do not arrive until Easter. Only emus stay all year round. We camped in a site by the artesian baths, a wonderful way to relax and learn about the immense subterranean artesian system that probably played a role in the development of the opal fields. We visited an underground opal mine and were allowed to fossick for opals on the ‘mullock heaps’ of old spoil outside the mine. My husband found a small sample but I was not so lucky.

Next day we headed northwards. I was disappointed I could not buy any black opals in Lightning Ridge because the shops were shut, but a few kilometres before crossing into Queensland, a roadside sign led to the house, shop and workshop of Greg Armstrong. An opal miner, cutter and stone setter. Greg laid out his collection of white and black opal (3) and when we mentioned we were learning lapidary, he gave us a bag of ‘potch’ opal to practice cutting at home.

Boulder opals from Quilpie, mined and cut by Eddie Lunney.

Over the state boundary, we headed north for St. George, Roma, where the oil and gas industry’s mega coal bed methane (CBM) project produces gas from extensive Permian and Jurassic coal deposits to supply the energy needs of c. 90% of the homes in Queensland, and the location of the famous Carnarvon Gorge.

We drove inland to central Queensland to The Gemfields area, which includes the localities of Anakie, Rubyvale, Sapphire and Emerald, where green gemstones initially taken for emeralds were found in about 1880, when drilling for water, ahead of railway construction. Green and yellow sapphires and zircons have been mined in this area since the 1880s.

Read more: Field Trip: The 'Emerald Desert' in Western Australia

At the Sapphire Caravan Park we watched wallabies and lorikeets being fed. Taking Jack Wilson’s advice, we looked for Peter and Eileen Brown at the Rubyvale Gem Gallery, but as they were on holiday, the shop manager showed us Peter’s amazing fancy cuts on parti-colour sapphires. The shop is a gemmologist's paradise. Alicia Pray was cutting beautiful black star sapphire cabochons from the Desperado mine, and we bought a bag of ‘wash’ from the mine to fossick back home in Scotland.


Coloured sapphires collected over a period of 40 years in The Gemfields of Queensland by Peter Brown of the Rubyvale Gem Gallery.

Alan, a lively Stranraer émigré, took us round an underground sapphire mine in Rubyvale. Prospectors first dug one metre diameter vertical shafts through ‘shin cracker’ overburden (sandy gravels). The bottom layer of wash sits uncomfortably over eroded granite. When miners hit the granite at a depth of 15 m or so, they dug horizontal tunnels to follow the alluvial pay zone where sapphires, zircons, garnets and occasionally diamonds concentrate. Miners knew if they found a block of quartz in the wash, and sapphires were present, they were likely to aggregate upstream of such ‘Billy boulders’. This helped them to orientate their tunnels.

Geological section c.15m below the surface inside the Walk-in Miners Heritage Sapphire Mine at Rubyvale. The alluvial sapphires concentrate within narrow 'wash zones' (average 15-20 cm as marked by dotted lines) above the 'granite floor' and below several metres of sandy alluvial gravels. Elongated features are pickaxe marks.

From The Gemfields in Queensland, we drove westwards to Barcaldine ahead of cyclone Debbie's rainclouds. Here we decided to head south towards the Quilpie opal fields. As the land became more arid, the soil turned red, the gum trees thinned out and the grass grew sparse. Intrepid wildlife competed with massive ‘road trains’ for the driver’s attention on the empty roads between the gem locations. We passed trucks hauling three trailers, sometimes four.

Arriving in Quilpie, everywhere we went we were presented with useful information, friendly advice and ideas for things to see, and a chance to cool down from the 35 °C heat of early autumn in the outback. In Quilpie, they told us St. Finbarr’s Catholic Church was worth a look. Its altar, font and lectern have impressive panels of boulder opal donated in 1976 by local miner Des Burton, the father of the boulder opal industry. I was quite literally on my knees in adoration.

The only shop open in Quilpie sells everything. There I found the last copy of Greg Pardey’s Black Opal: A Comprehensive Guide to Cutting on its shelves and read it cover to cover before we got back to the UK. Walking back to the motorhome on our way out of town, we noticed that the Opal Hunter shop had opened too. Asking if I could buy some rough opal to cut back home, shop owner Eddy Lunney told me he would need to get to know me before knowing what he wanted to sell me. Induction into opal heaven started with a tour of the shop, the lapidary workshop and the yard with part of his huge stock of boulders from his opal mine. By teatime he had given me a masterclass in boulder opal cutting and polishing. I absolutely loved it! The dark blue and purple colours he brings out of the transparent opal (known as crystal) are gorgeous. It was really hard to leave Quilpie the next morning.

We noticed a change in the weather. The temperature had dropped to 20 °C as we drove to Yowah. In this famous opal location, we found Scott Shorten, shopkeeper, opal mine tour guide and librarian. After lunch, with his shopkeeper hat on, he showed us round the Yowah Opal Centre. Yowah opal is found inside nodules. Nine out of ten nodules are empty, so it is always exciting to crack open one, using a hammer or even better sawing through it, to see whether there is any opal inside. Scott sold us some good samples.

Before flying home, Matthew Morin FGA FCGmA senior sales consultant at Altmann + Cherny, a jewellers on Sydney’s Pitt Street, showed me how beautiful opals are used in modern jewellery (6). The shop also hosts The Olympic Australis, the largest and most valuable piece of opal ever found. It is a white opal from Coober Pedy, which weighs 17,000 ct, measuring 28 cm long by 11.5 cm high. For more information visit altmanncherny.com.au/famous

ACKNOWLEDGMENTS Carmen Garcia-Carballido would like to thank her husband, Peter Scott-Wilson, for organising the wonderful tour. Eddy and Lynda Lunney for their hospitality at Quilpie. Jack and Dallas Wilson, Robert Cook, Greg Armstrong, Scott Shorten, the staff at Rubyvale Gem Gallery and Matthew Morin for generously giving their time to discuss Australian gemstones.

Carmen meeting Matthew Morin at Sydney jewellers Altman + Cherny. Matthew is also the president of, and a gemmology tutor at the NSW division of the GAA (The Gemmological Association of Australia). Carmen is modelling a Koroit boulder opal pendant on white gold from the shop. Image by Peter Scott-Wilson.


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 Yowah boulder opals cut by Scott Shorten. Image by Carmen Garcia-Carballido.


Don't Miss the Summer 2019 Issue of Gems&Jewellery!

Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online. 

Read more


Breaking down the Misunderstandings about Precious Coral

Breaking down the Misunderstandings about Precious Coral

Inspired by Pantone’s ‘Color of the Year 2019’, Rui Galopim de Carvalho FGA DGA dives into the underwater world of precious coral and addresses some of the misunderstandings around its use in the jewellery industry.

Read more


Additional Info

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Speaker in the Spotlight: Q&A with Evan Caplan

One of the key speakers at this year's Gem-A Conference, Evan Caplan will discuss everything about the extraordinary gemstone, alexandrite including a little history, information on sources (old and new), colour change, cutting, along with some fun stories about his travels and experiences with alexandrite.

We caught up with Evan Caplan to secure some exclusive insider knowledge and find out exactly why he's known as the "eye" within the industry ahead of this talk, 'The Magic of Alexandrite'...

Q. What is it about alexandrite in particular that fascinates you?

When I saw my first alexandrite, I thought it was really ugly. It was brownish and had a slight change of colour. I didn't know or understand why people were so excited about this particular stone. For years, almost every stone I had seen was very similar to that first one. I used to say "I don't care if it changes colour, it's ugly". Then, the material from Brazil was discovered. This material was beautiful. It went from blueish green to a reddish purple. The change of colour was beautiful and dramatic. Most of this material was clean and well cut too. That dramatic colour change is what fascinates me to this day.

Q. Many professionals refer to you as “the eye”, what does that mean and how does that shape your passion for coloured gemstones?

I seem to have an eye for beautiful stones. I can look at a parcel and my eye immediately goes to the best stones in the lot. It's probably more of an educated taste, if that makes sense. Stones with great colour, clarity and cutting are what turn me on.


Polished alexandrite showing pleochroism (two colours) under the same light source.
Image ©Barbara Kolator, Gem-A.

Q. To those attending your talk at the Gem-A Conference 2017, what piece of knowledge do you wish for them to walk away with?

I hope people leave my talk with an understanding of the difference between an ok stone, a good stone, and a great stone, along with a new appreciation of alexandrite.

Q. In your opinion, what coloured gemstones are the most rare and valuable worldwide?

To me the three rarest and most valuable coloured stones are great alexandrite's, great padparadschas and great Brazilian paraiba's.


Green stone; Piece of rough alexandrite showing colour change, green in daylight.
Image ©Barbara Kolator, Gem-A.


 Red; same rough alexandrite stone under incandescent light showing red colour.
Image ©Barbara Kolator, Gem-A.

  • 'The Magic of Alexandrite’ by Evan Caplan will take place Saturday 4 November 2017 at 14:30-15:30pm.
  • To purchase your tickets to Gem-A Conference 2017 and full listings of the programme, please visit the official website here.

 

Interested in finding out more about gemmology? Sign-up to one of the 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 Evan Caplan and a selection of chyrosberyl alexandrite stones showing colour change. Images ©Barbara Kolator, Gem-A.


Don't Miss the Summer 2019 Issue of Gems&Jewellery!

Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online. 

Read more


Breaking down the Misunderstandings about Precious Coral

Breaking down the Misunderstandings about Precious Coral

Inspired by Pantone’s ‘Color of the Year 2019’, Rui Galopim de Carvalho FGA DGA dives into the underwater world of precious coral and addresses some of the misunderstandings around its use in the jewellery industry.

Read more


Additional Info

Read more...

How to Separate Natural from Synthetic Ametrine using Conventional Equipment

Guy Lalous ACAM EG summarises the discovery of features that could be used to distinguish between natural and synthetic ametrine from The Journal of Gemmology; from the orientation of growth striations to the interference patterns caused by twinning.

What about natural ametrine?

Ametrine is a bicolored quartz variety that contains both amethyst and citrine zones in the same crystal. The only significant source of natural ametrine is eastern Bolivia’s Anahi mine, where it occurs in veins in a dolomitic limestone. The amethyst-citrine bicoloration results from quartz precipitation at very specific geochemical conditions, temperatures, and growth rates. The combination of amethyst and citrine colours in natural ametrine from the Anahí mine has been attributed to colour zoning that differentiates rhombohedral r (violet) and z (yellow) growth sectors.

The colour of iron-bearing quartz depends on the valence state of the iron. The citrine colour in Bolivian ametrine appears to come from the incorporation of very small aggregates of Fe3+. The amethyst colour develops in two steps. First, individual Fe3+ ions replace Si4+ ions in the quartz structure. To develop the amethyst colour, the crystal must be exposed to ionizing radiation to oxidize the iron in the 4+ state.

Shown in this composite photo are three custom-faceted natural ametrines: a 19.87 ct round StarBrite cut, a 20.35 ct cushion ZigZag cut and a 13.69 ct square StarBrite cut. Courtesy of John Dyer Gems, Edina, Minnesota, USA; photos by Ozzie Campos.

What about FTIR?

FTIR is a technique that measures absorptions within the infrared part of the electromagnetic spectrum. In infrared spectroscopy, IR radiation is passed through a sample. Some of the infrared radiation is absorbed by the sample due to vibrations of molecules in the crystal structure and some of it is transmitted. The resulting spectrum represents a molecular fingerprint of the sample. Infrared spectrometry is very useful to detect impregnations in gemstones (polymers, oils and resin), heat treatment in corundum and to distinguish certain natural and synthetic gem materials. Full width at half maximum is the width of the spectrum curve measured between those points on the y-axis, which are half the maximum amplitude.

What about EDXRF?

X-Ray fluorescence analysis using ED-XRF spectrometers is a commonly used technique for the identification and quantification of elements in a substance.

Beginning in 1994, Russian gem-quality synthetic ametrine entered the market. Synthetic ametrine can be identified by employing advanced techniques, such as EDXRF chemical analysis, and IR spectra. High-resolution (0.5 cm-1) FTIR analysis has shown that a band at 3595 cm-1 is present in the vast majority of natural amethyst. If the 3595 cm-1 band occurs in synthetic amethyst, it has a much larger FWHM (Full width at half maximum) value than in natural specimens. EDXRF chemical analyses revealed higher concentrations of K, Mn, Fe and Zn than in natural ametrine.

What is a conoscope?

The conoscope is a polariscope accessory tool. It is a strongly converging, strain-free glass sphere. When a gemstone is positioned between two crossed polarizers, interference colors that are centered in the specimen will be witnessed with the conoscope when the optic axis is exactly perpendicular to the polarizers.

Previous studies focused on the possibility to separate natural from synthetic ametrine using the refractometer and the polariscope. Quartz is a uniaxial mineral with two unique refractive indexes along its three crystallographic axes. The unique axis is the optic axis. The amethyst-citrine colour boundary in natural ametrine is oriented roughly parallel to the optic axis; in synthetic stones, the boundary is oriented at an oblique angle to the optic axis. The gemmologist needs only to find the direction of the optic axis to determine whether an ametrine is natural or synthetic.

The optic axis in a uniaxial gemstone can be found with a polariscope that has a conoscope lens and, on occasion, with a refractometer. The direction of the optic axis cannot be obtained by refractometer readings for samples cut with their table at random orientation to the optic axis and some difficulties may arise with samples displaying complex colour zoning or twinning.

In this article, the authors explain the possibilities for separating natural from synthetic ametrine by microscopic examination. The immersion microscope was used to look for twinning features, to establish the orientation of the violet/yellow colour boundaries and the direction of growth striations relative to these boundaries, and to observe any characteristic inclusions.

Faceted natural ametrine gemstones from Bolivia typically display only two colour zones, as seen here viewed toward the table facets (top) and toward the pavilions of the same samples (bottom). The stones weigh from 2.45 to 7.45 ct (upper left, 11.7 × 10.8 mm). Photos by K. Schmetzer.

 What are Brewster fringes?

Amethyst from worldwide localities is commonly Brazil-law twinned, which is an intergrowth of right- and left-handed quartz. Such twinning is evidenced only by examination under polarized light. It results in sectors which, when viewed perpendicular to the c-axis, show symmetrical trigonal patterns of dark bands known as Brewster’s fringes. In Bolivian ametrine, these fringes are found only in the alternating amethyst sectors, and not in the citrine sectors.

Between crossed polarizers, the samples show interference patterns (Brewster fringes) that indicate Brazil-law polysynthetic twinning of the violet r growth sectors. Photomicrographs by K. Schmetzer, in immersion.
Optical FeatureNaturalSynthetic
Twinning

Violet growth sectors are intensely twinned on the Brazil law, showing various forms of Brewster fringes with crossed polarizers;
yellow growth sectors are not polysynthetically twinned.

Violet and yellow growth sectors are primarily untwined; small areas within the violet growth
sectors may be twinned on the Dauphiné and/or the Brazil law.

Violet/yellow boundaries Mostly parallel to the c-axis or only slightly inclined to the c-axis (up to about 10°).

Inclined between 20° and 38° to the c-axis.

Growth striations Violet growth sectors: inclined at about 67° or 38° to the violet/ yellow boundary; yellow growth sectors: none observed.

Violet growth sectors: parallel or almost parallel to the violet/ yellow boundary, mostly inclined
at angles between 0° and 8°, with a maximum inclination of 18°; yellow growth sectors: very
weak striations parallel to the basal face.

Fluid inclusions

Rare fluid inclusions, occasionally reflecting the polysynthetic twin pattern of the violet growth zones.

Rare two-phase (liquid and gas) inclusions elongated parallel to the c-axis.

Table showing diagnostic features of natural and synthetic ametrine using immersion microscopy.

The microscopic procedure for identifying these key features can be summarized as follows. The examination of a faceted sample of unknown origin should begin by orienting the dominant colour boundary perpendicular to the rotation axis of the sample holder. If the stone is natural, the typical interference pattern with Brewster fringes will be revealed upon rotation of the sample.

Furthermore, growth striations inclined at relatively large angles to the colour boundary will be observed in the violet portion of the stone after a rotation of about 40° versus the c-axis. If the sample is synthetic, rotating the sample generally will not bring the optic axis into view, and violet growth striations parallel or at a small angle to the violet/yellow colour boundary frequently will be present. It is possible to find the optic axis in a synthetic sample by moving it to other orientations within the sample holder, in which case an untwined interference figure normally will be seen.

In natural ametrine, the colour boundary between the violet r and yellow z growth zones more-or-less follows a prismatic m crystal face but is not exactly planar. In addition, growth striations are present in the violet r sectors, and they are parallel to an external r face and inclined to the violet/yellow boundary. The angle between the growth striations and the colour boundary measures approximately (A) 67° or (B) 38°. Photomicrographs by K. Schmetzer, in immersion.

Separating synthetic ametrine from its natural counterpart using conventional gem lab equipment is possible, provided that the gemmologist has a good understanding of the morphology and optical mineralogy of both natural and synthetic material. The authors insist to use immersion for microscopic observations as the various patterns or structures observed without are of less diagnostic value.

This is a summary of an article that originally appeared in The Journal of Gemmology entitled 'Distinction of Natural and Synthetic Ametrine by Microscopic Examination - A Practical Approach' by Karl Schmetzer 2017/Volume 35/ No. 6 pp. 506-529

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: Crystal clusters that occupy the storage room of the company Minerales y Metales del Oriente in Santa Cruz, Bolivia. Only small portions of the crystals are of facetable quality. Photo taken in 1997; courtesy of Udo Reimann.


Don't Miss the Summer 2019 Issue of Gems&Jewellery!

Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online. 

Read more


Breaking down the Misunderstandings about Precious Coral

Breaking down the Misunderstandings about Precious Coral

Inspired by Pantone’s ‘Color of the Year 2019’, Rui Galopim de Carvalho FGA DGA dives into the underwater world of precious coral and addresses some of the misunderstandings around its use in the jewellery industry.

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Additional Info

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Gemstone of Passion: Padparadscha sapphire

Considered to be among the most beautiful of the corundum gems with its delicate colour, Padparadscha sapphire has recently hit the headlines thanks to Princess Eugenie of York’s engagement ring. Here, we explore this majestic gemstone fit for royalty.

Om mani padme hum – “Hail the jewel in the heart of the lotus”
- Buddhist Mantra

With recent royal exposure placing this gemstone in the media limelight, the public has been left with a burning question - what exactly is a Padparadscha sapphire?

Whilst considerably unknown to most, Padparadscha sapphires, recognisable for their delicate salmon pink tones, are prized among connoisseurs of the gem world. Just like other sapphires, the Padparadscha has a hardness of 9 on the Mohs scale, making it one of the hardest gemstones in the world (and ideal for engagement rings!). 

Sapphires get their colour from different trace elements. The presence of iron and titanium is responsible for blue tones, while traces of chromium cause pink tones. Ruby red is a result of more chromium present in the stone’s chemical composition. The Padparadscha sapphire is the rarest form of sapphire corundum, balancing on the colour boundary between pink and orange.

Deriving from the Sinhalese word for ‘aquatic lotus blossom’, the Padparadscha has stirred much debate amongst gemmologists, buyers and collectors about what colour spectrum constitutes a Padparadscha over, say, a pink sapphire or orange sapphire. Like all gemstones, Padparadscha sapphires are not easily identified as they have their own individual colour zoning with some displaying lighter mediums of pink and orange or colour zoned with yellow. In terms of value, this type of sapphire increases in value as the saturation of colour increases.

The rarity of these sapphires is due to their limited locale and sourcing. Whilst commonly found in Sri Lanka, Padparadscha sapphires are also found in Tanzania and Madagascar. Padpardaschas sourced from Madagascar are usually pinker than orange but now contribute to a wide percentage of the stones available on the market today, whilst those from Tanzania tend to be browner. Whilst many gemmologists insist that the only ‘real’ Padpardschas come from Sri Lanka, new sapphires from Madagascar continue to be a beautiful and unique addition to the market supply. 

Read more: An examination of the problem of separating pink sapphire and padparadscha from ruby

Today, many Padparadscha sapphires from Madagascar are heat-treated to enhance their pinkish colour at much lower temperatures to those sourced from Sri Lanka. A widespread treatment for corundum that induces the orangish-pink colour is Beryllium diffusion. The market is awash with these treated stones, therefore a lab report is essential when purchasing a naturally coloured Padparadscha sapphire.

Of course, Padparadscha sapphires have caught the attention of the media since Princess Eugenie of York, the granddaughter of Her Majesty the Queen and daughter of Prince Andrew, Duke of York, and Sarah Ferguson, Duchess of York, got engaged to wine merchant, Jack Brooksbank, in January 2018.

Her ring, which is not dissimilar to the ring Prince Andrew presented to Sarah Ferguson in 1986, features an oval-cut Padparadscha sapphire surrounded by a halo of diamonds. This is set on a yellow gold band with two further tapered diamonds at the shoulders.

Will Padparadscha sapphires be the surprise hit of 2018? Perhaps the Tucson and JCK trade events in January and June, respectively, will reveal a surge of popularity for this particularly lovely sapphire.

Gem-A would like to thank Richard Hughes of Lotus Gemology for his support in compiling this article. 

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: Princess Eugenie and Jack Broosbank via The Royal Family, Instagram. A 4.5ct unheated Padparadscha sapphire ring courtesy of the Somewhere In The Rainbow Collection


Don't Miss the Summer 2019 Issue of Gems&Jewellery!

Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online. 

Read more


Breaking down the Misunderstandings about Precious Coral

Breaking down the Misunderstandings about Precious Coral

Inspired by Pantone’s ‘Color of the Year 2019’, Rui Galopim de Carvalho FGA DGA dives into the underwater world of precious coral and addresses some of the misunderstandings around its use in the jewellery industry.

Read more


Additional Info

Read more...

Birthstone Guide: Emerald for Those Born in May

Those born in May are lucky enough to count emerald as their birthstone. Here, Gem-A gemmology tutor, Lily Faber FGA DGA EG, explores the history and qualities of this beautiful green beryl. 

The emerald is arguably the most well-known and desired member of the beryl family with its brilliantly verdant colour. Green stones have been called emeralds for thousands of years -  since around 4,000 BC - regardless of whether they actually were what we know as emeralds today.

Emerald Lore

At one time, emeralds were believed to give one the ability to predict the future, especially when held underneath the tongue. They were also believed to confer riches upon the wearer and were used as protection against poison and demonic possession. Used as a symbol of immortality and wealth, emeralds have been valued for centuries for both their appearance and symbolism.

 Beryl Emerald Crystal in Calcite Matrix and Carbonaceous 9767 GemA PDEmerald crystals in calcite. Photographed by Henry Mesa.

Finally, it is said that emeralds are beneficial for the eye and it is reported that some lapidaries keep an emerald on their bench to look at, giving relief to their  tired eyes after a long day of cutting gems.

Emerald Localities

Emeralds have been mined for thousands of years, stretching back to Egypt near the Red Sea around 2000 BC in what were known as Cleopatra’s emerald mines. While Egyptian emeralds were some of the first to be mined and traded, it was the discoveries of Colombian emeralds by 16th century Spanish conquistadors like Pizarro that brought strikingly saturated green crystals to the European market - particularly to the Spanish court and beyond.

Emerald Crystal Emerald and Emerald Cut Connection Gem A BlogA large Colombian emerald crystal. Photograph by Henry Mesa. 

It is still thought that emeralds from the Colombian mines such as Chivor, Muzo and Cozquez are the finest in the world. Other localities that produce emeralds are Brazil, Russia, India, Zambia, Zimbabwe, Madagascar and North Carolina, USA. 

Emerald Crystals and Inclusions

Emeralds typically form as hexagonal prisms with a flat pinacoid top and base. Sometimes, they can have rectangular etch pits on the prism faces and hexagonal etch pits on the top of the crystal.

Pyrite Inclusion in Emerald.

Due to their brittle nature, these gemstones often have internal fractures along with many different types of inclusions. Emeralds are routinely oiled or even resin-filled, to reduce the appearance of these internal fractures. It is possible to see a blue or yellow flash within the stone if it has been filled with a resin, but careful observation is needed. 

Read more: What Can Emerald Inclusions Tell Us About Their Origin? 

Also found in Colombia are trapiche emeralds, in which an emerald forms with a central, hexagonal crystal from which radiate six emerald segments that are separated by a fine-grained mixture of colourless beryl and nearly black albite.

Emerald Trapiche. Photo by Pat Daly

Inclusions are numerous and varied, and sometimes one can tell where the emerald was mined based on what lies inside the gemstone. Colombian emeralds, for example, typically have three-phase inclusions, which consist of a liquid, a solid mineral inclusion and a gas bubble contained in a jagged cavity.

Read more: What Makes a Gemstone Rare? 

Other inclusions typical of their localities are comma-shaped two-phase inclusions found in Indian emeralds, and long, curved tremolite inclusions in emeralds from Zimbabwe. There are many other inclusions such as bamboo-like actinolite, pyrite and colourless rhomb-shaped crystals.

 
Three Phase Inclusion in Emerald.

Emerald Cut and Use in Jewellery 

There is a type of square or rectangular step-cut with truncated corners that is so often used for this gemstone that it is more commonly known as the emerald cut. The corners are removed so as to protect the brittle stone from unwanted chipping and breakage at the stone’s most vulnerable points.

Read more: What is the Link Between an Emerald and the Emerald Cut?

Claw settings are used, particularly at the corners and along the sides, but a more practical setting would be the bezel or rub-over setting in order to form a barrier around the entire stone. Whether you love emeralds or prefer another type of beryl, there is no arguing that its deep green colour and lore make it a gemstone to be admired. 

Start your gemmology journey with a Gem-A Workshop, designed to get you up-to-speed with the basics of gemstones. Find out more here

The Gem-A Gemmology Foundation course is the ideal way to turn your passion for gemstones into something more. Discover all our gemmology courses here

Cover image: Emerald in quartz by Henry Mesa.

Additional Info

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Focus on Fluorescence: Looking for the Light

Most of us know about fluorescence in gemstones, but how many use it as part of their gemmological testing routine? Here, Gem-A gemmology tutor Lily Faber, FGA DGA EG, delves deeper into fluorescence and explains why it can be both enlightening and enjoyable for gemmologists.

A bag of cubic zirconia under LWUV with areas of blue fluorescence that highlights the presence of diamonds. 

When we use the term luminescence in gemmology, it generally refers to the term photoluminescence, which is the emission of a cold, visible light when a gem material (or general substance) is excited by light of a shorter wavelength. Two examples are fluorescence and phosphorescence. Fluorescence occurs when a gem material is illuminated by radiation of shorter wavelengths with higher energy.

READ MORE: Leading the World's First Gemstone Testing Laboratory: Gem-A's Basil Anderson

The visible light emitted stops when the source of illumination is turned off. Phosphorescence, on the other hand, is a visible light that is emitted by a gem material after the original source of exciting radiation has been switched off. A famous example of a gemstone that strongly phosphoresces is the blue Hope Diamond, which glows a bright red for several minutes after being excited by short wave UV light. Both fluorescence and phosphorescence can have varying strengths from very strong to weak. If a material does not either fluoresce or phosphoresce, it is considered inert.

Quartz under LWUV showing oil inclusions.

HISTORY OF FLUORESCENCE
Fluorescence has been observed for years, but it was not until Sir George Stokes extensively documented this effect in relation to gemmology that it officially became part of the scientific lexicon. In 1852, Sir George coined the word fluorescence, named after fluorspar, more commonly known as fluorite, which is a highly fluorescent material. The ‘Stokes Law of Fluorescence’ or ‘Stokes Shift’ states that the fluorescent emission of light will always be that of a longer wavelength than the excitation source, i.e. the light emitted is of a lower energy than its excitation source.


Mangano Calcite fluorescing under LWUV.

WHY USE FLUORESCENCE?
Fluorescence can be a helpful tool when used correctly. Some gemstones have a characteristic or, very rarely, a diagnostic reaction to UV light. One gemstone that notably both fluoresces and phosphoresces is a diamond, which typically fluoresces blue in longwave UV light and then phosphoresces yellow. This is a diagnostic result for a colourless to yellow diamond in the Cape series (Type Ia), but please be aware that fluorescence is rarely diagnostic as reactions may vary wildly within the same species or variety of gemstone.

READ MORE: The Fascinating History of Platinum

Fluorescence can indicate or confirm the identity of a stone. For example, citrine quartz is inert to fluorescence due to the presence of iron, which eliminates fluorescence. If you are testing a yellow stone that may potentially be a citrine, and it fluoresces orangey-yellow under LWUV and red under SWUV, it cannot be a citrine and is more likely to be a scapolite.


Scapolite from Ontario under LWUV.

Other reasons to use fluorescence? It is quick and normally takes less than one minute to observe reactions. You can test gemstones that are loose, set, rough or fashioned, and you can test either single gemstones or multiple gems at the same time. Finally, it is entertaining!

HOW DOES IT WORK?
Ultraviolet light (UV) is the most commonly used excitation source. We cannot see UV light as it sits just below the visible light spectrum (400nm- 700nm) at 10-400nm. UV light enables us to see fluorescence because a gem material will absorb this radiation source and then emit light that is lower in energy and therefore visible to the eye. But what is actually happening within the gemstone itself to elicit such a colourful reaction? It has to do with electrons. When electrons are excited by a source of radiation, they jump to a higher energy level around the nucleus of the atom. The excited electron remains in this excited state for a short period of time until it falls back to its original ground state. As the electron returns to its ground state, it emits energy either as heat or as visible light (fluorescence).


A: Natural spinel, red paste, synthetic verneuil ruby, almandine garnet and two natural rubies.
B: The same stones under LWUV. C: The results under SWUV.
 

If you are wondering if all minerals fluoresce, the answer is no. Only 15% of all known mineral species exhibit this effect, the causes of which can be very complex. One of the more better-known and documented causes is the presence of activator elements that can be excited by higher energy wavelengths. Some activators include chromium (Cr), uranium (U), manganese (Mn), lead (Pb), titanium (Ti) and rare earth elements (REE). Some elements are considered to be the complete opposite, however, and when present they eliminate or quench fluorescence, causing a gemstone to be inert. Common quenchers include iron (Fe) and nickel (Ni).

 
Kunzite under SWUV.

HOW TO SAFELY USE UV LIGHT FOR TESTING
The types of UV light used in testing are long wave (LWUV) with a principle wavelength of 365nm, and short wave (SWUV) with a principle wavelength of 254nm. Different testing equipment ranges from UV keyrings (typically LWUV) to a UV viewing cabinet. When using UV light to test gemstones, it is important to remember that any exposure to UV light can damage your eyes, but particularly use caution when using SWUV as it is more dangerous than LWUV. Always wear protective UV goggles or ensure that your UV cabinet is installed with an eyepiece that filters out UV light.

To properly use a UV keyring, take the following steps:

  • Never look directly into the light
  • Turn off surrounding lights so you are in a dark environment.
  • Place the gemstone table-down if facetted. If table up, the gemstone may reflect the UV light into your eyes and creating confusing, conflicting or inconclusive results.
  • Hold the keyring approximately two inches away from the stone and, if testing multiple gems, always be consistent with the distance at which you hold the light.
  • Record whether the stone is inert or fluorescing, and the strength of the reaction.

Sometimes you may see some dull purple or red light in the gemstone or on a few facet edges. This means that the gemstone is reflecting the purple UV light and is not itself a fluorescent reaction.   


A: Synthetic verneuil sapphire, scapolite, natural sapphire, topaz and citrine. B: Under LWUV. C: Under SWUV 

UNDERSTANDING THE RESULTS
While fluorescence is not a diagnostic test, and results can vary dramatically even within the same gemstone species (variable emerald results, for example), it can be a useful indication of what a gemstone is. When testing diamonds and colourless, transparent simulants, keep the below chart in mind. When testing red to pink gemstones,do keep in mind that natural rubies in particular may have variable fluorescence based on their iron content. If iron is present, the ruby will have minimal to no fluorescence. Synthetic rubies tend to have much stronger fluorescent reactions.

READ MORE: Birthstone Guide: Sapphire for Those Born in September

When testing green gemstones, fluorescence can be tricky to use for identification purposes. However, it may be useful in terms of recognising the presence of fillers in emeralds or green jadeite jade, for example. Some resin fillers fluoresce a whitish colour under LWUV and if this reaction is seen in either of the aforementioned stones, it may be an indication that filler is present, especially if the fluorescence is concentrated in seams or certain areas rather than being evenly distributed across the stone.

Note the natural emerald fluorescing a whitish colour (second from right), hinting that a resin filler may have been used. Further testing will be needed to confirm this possibility.

Left to Right: synthetic flux emerald, synthetic hydrothermal emerald, natural emerald, chrome diopside.

Additionally, natural emeralds, if they do fluoresce, will have a red to inert reaction under LWUV, and a weaker inert or green reaction under SWUV. Synthetic emeralds may fluoresce red or, in the case of the synthetic hydrothermal emerald, they may be inert if doped with iron to imitate a natural inert reaction. Untreated green jadeite does not fluoresce, so any other reaction should be regarded with suspicion and further testing will be needed. When testing yellow gemstones the bottom chart may prove useful.

CONCLUSION
As is evident, fluorescence can be a helpful tool when testing gemstones, though not always diagnostic. It is a quick test that is one of the more exciting ones in the world of gemmology. ■

All images courtesy of Lily Faber and Gem-A gemmology tutor, Pat Daly.

 

Colourless Gemstones

LWUV

SWUV

Diamond (natural)

Strongest reaction, most common is blue, but can be yellow and green

Similar colours to LWUV but it is a weaker reaction

Diamond (synthetic)

Similar colours to SWUV but it is a weaker reaction

Strongest reaction, mainly fluoresce orange to yellow

Cubic zirconia

Yellow to dull-orange, variable

Weaker reaction to LWUV or inert, similar colours

Synthetic moissanite

Variable reactions

Variable reactions

Synthetic spinel

Inert

Bright, chalky white or blue/green

Paste

Inert

Variable, may have chalky white surface

Red and Pink Gemstones

LWUV

SWUV

Ruby (natural)

Variable, strong red to inert

Same as LWUV but weaker to inert reaction

Ruby (synthetic)

Bright red, tends to be stronger than natural ruby

Red, weaker than LWUV but still brighter than natural ruby

Red spinel

Red

Red, but weaker than LWUV

Spodumene, var. Kunzite

Orange or violet

Weaker violet, whitish or inert

Almandine garnet (Iron is present, this stone never fluoresces)

Inert

Inert

Red glass/paste

Inert

Variable, may have chalky white surface

Yellow Gemstones

LWUV

SWUV

Quartz, variety cirtrine

Inert

Inert

Yellow sapphire (natural)

Apricot orange to inert

Inert

Yellow sapphite (synthetic)

Weak red to inert

Inert

Yellow scapolite

Yellowish

Reddish

Yellow topaz

Yellowish

Whitish

 

This article originally appeared in Gems&Jewellery Summer 2018/ Volume 27/ No.2 

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: Willemite and calcite fluorescing under SWUV.


Don't Miss the Summer 2019 Issue of Gems&Jewellery!

Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online. 

Read more


Breaking down the Misunderstandings about Precious Coral

Breaking down the Misunderstandings about Precious Coral

Inspired by Pantone’s ‘Color of the Year 2019’, Rui Galopim de Carvalho FGA DGA dives into the underwater world of precious coral and addresses some of the misunderstandings around its use in the jewellery industry.

Read more


 

Additional Info

Read more...

Speaker in the Spotlight: Q&A with Peter Lyckberg

As we eagerly anticipate the Gem-A Conference 2018 next month, we chat to speaker Peter Lyckberg ahead of his presentation on the gem deposits of Afghanistan and Pakistan.

Q. You’ve said that you were first fascinated by minerals after finding muscovite, quartz and red kalifeldspar at your grandparents’ home, what in particular captivated you?

These very first samples, all fitting in the matchbox that was my first mineral collection, had different colours and all looked different i.e a variety of physical properties. The silvery transparent cm-sized thin muscovite sheets, red feldspars with cleavage and the irregular white quartz grains, all between grey granite gravel.

These optical observations of three minerals in one rock kickstarted my interest - truly, it was the colours and shapes that captivated my mind. Later, aged eight, I started to find rare black minerals such as columbite and plumbomicrolite and thus I became interested in the chemistry of minerals.

Q. Your studies of minerals in situ have taken you around the globe, have you noticed any trends at ore deposits in the last decade that have impacted on the industry? 

The last decade has seen an incredible suite of new deposits; some of them have equalled or even surpassed previous finds on the globe. This extended activity in more and more countries makes this point in time a golden age for minerals and gems.

Q. What drew you to Pakistan’s Karakorum Mountains, and what is special about the deposits there?

The exceptional high quality of pristine aquamarine, topaz, tourmaline crystals preserved on matrix (i.e. still attached to their mother rock) from the Karakorum, followed by many rare species of extraordinary quality, is what makes this region so special. The pegmatites are very young and the mountains are still rising.

The specific conditions of formation are always intriguing, and my life’s interest is simply to visit veins and deposits in situ to study them in detail to understand, as well as we can, the correct and exact place of origin.

Shigar Matrix. Image Credit Peter Lyckberg.

Q. What do you particularly love about being a mineral researcher? 

If you have a curious mind you simply have to find answers, or try to do so to a satisfactory level.

If the literature is incomplete you must go on-site to document yourself. No matter if this is in the high mountains, or in a deep dark mine, the reward comes when you see a pocket in situ and can observe and document all the parageneses, see which minerals formed where in the pocket, how they vary within a pocket, and between each pocket. It is a limitless track to knowledge waiting to be explored.

Q. As we eagerly anticipate your talk at the 2018 Gem-A Conference, what are you most looking forward to when you visit London this November?

The chance to meet and interact with new British colleagues, and those from various corners of the world. I am also looking forward to hearing the presentations. If I learn one new aspect or gain one piece of precious knowlege, then it is well worth the trip!

If we are lucky, we will be enlightened with images of new stones we may have not seen before. Then London in itself, including the Crown Jewels, is certainly the icing on the cake!

About Peter Lyckberg

Sweden-born Peter Lyckberg is a lifelong mineral researcher. He has travelled the world to study the geology and mineralogy of gem and ore deposits in situ. His interest started as a toddler finding muscovite, quartz and red kalifeldspar among the grey granite gravel on his grandparents’ walkway.

Later, he studied civil engineering and geology at Chalmers University of Technology. Lyckberg is well-known for his knowledge of mineral deposits, including gem pegmatite fields in Norway, Sweden, Finland, Ukraine, Russia (Ural Mountains, Transbaikal), Afghanistan, Pakistan, Namibia, Brazil, California and Maine.

He is also acknowledged as a confident speaker and experienced writer of 60 articles and book chapters on the topics of gemmology, geology and mineralogy. He has served on the editorial board for several mineralogical journals since 1985. Lyckberg is an independent researcher and scientific collaborator with the Museum of Natural History in Luxembourg. For the past 21 years he has worked as a nuclear inspector for the European Commission in Luxembourg.

If you would like to join us in London this November and hear  our expert speakers click here and register for the Gem-A Conference 2018.

If you are a Gem-A Member or Student you will have received an email to book member or student rates, if you haven't received it please contact membership@gem-a.com.

Cover Image: Peter Lyckberg in the Karakorum Mountains, Pakistan.


Don't Miss the Summer 2019 Issue of Gems&Jewellery!

Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online. 

Read more


Breaking down the Misunderstandings about Precious Coral

Breaking down the Misunderstandings about Precious Coral

Inspired by Pantone’s ‘Color of the Year 2019’, Rui Galopim de Carvalho FGA DGA dives into the underwater world of precious coral and addresses some of the misunderstandings around its use in the jewellery industry.

Read more


Additional Info

Read more...

Speaker in the Spotlight: Q&A with Monica Stephenson

With only a few weeks to go until the 2018 Gem-A Conference, we chat to ANZA gems founder Monica Stephenson ahead of her talk 'A Responsibly Journey: One Woman's Trip into a Gem Mine'

Q. What initially peaked your interest in the world of gemstones and mining in particular?

I’ve had a lifelong love affair with jewellery, beginning in childhood, but it chose me for a career during college.  While I’ve always worked with and admired designer jewellery, I wasn’t completely aware of the gemstone world, complete with its colourful cast of characters, until about 2013.  That was when I saw a tweet about a feature documentary, Sharing the Rough, that was filming the story of a gemstone from the dirt in East Africa to a finished piece of high jewellery.  I was hooked, and eventually ended up in Tanzanian and Kenyan gemstone mines for the filming!  What I saw there--passionate people working tirelessly to unearth colourful treasures--changed the course of my life.  I figured out how to connect all the dots in my jewellery experience to help bring gorgeous gems to market--and hopefully help the East Africans participate more in the global gem trade.  

Tsavorite. Image credit: Monica Stephenson

Q. You have a background in jewellery writing and jewellery design - how do you think these areas have shaped your career to date and how useful are they as an 'accidental gem dealer'?

I’ve been in the jewellery industry a long time, in all kinds of roles: salesperson, buyer, entrepreneur, and I helped to launch Amazon’s jewellery business.  I started writing about jewellery in 2008 on my blog, idazzle.com.  My children were very small and writing was something I could do on my time, on my own terms.  I focused a lot on independent, artisan jewellery designers, wanting to know what made them tick.  Somewhere around 2013 or so, I became increasingly interested in responsible jewellery topics.  All of these incredible connections to thoughtful designers and people in the industry doing the right thing, focusing on the people in the supply chain, meant that I had all these relationships to draw on when gemstones became my focus.  I never dreamed when I was writing about some of these people that I would be working with them, collaborating! Every experience in my life combined to make pursuing ANZA Gems as a natural extension of my experience.

READ MORE: Speaker in the Spotlight, Wallace Chan

Q. Can you remember your first gem mining experience - how did it impact you?

Vividly!  It’s absolutely at the heart of why I focus on gems and East Africa!  On my first trip in 2014 for the film, I had finally made it to Kenya and after a couple of days there I was enthralled with the landscape, the people, the sheer beauty of it all.  But then I found myself standing at the top of this big hole in the ground...peering down towards the tsavorite mine entrance of the bottom...wondering if I was actually going to go in.  You’ll have to come to the conference to hear the rest, but seeing the reality of where gemstones truly come from--the sweat, the callouses, the bats--changed how I see gems and how we value them. 


Image credit: Monica Stephenson

Q. What are some of your fondest memories of travelling to gem locations?

Ahhh...driving through the African savanna, the windows open and the wind in my hair, the red dirt and acacias hurtling by, and baobab trees, giraffes, and elephants encountered along the way…I pretty much love everything about it.  You have to be able to handle the “roads”--often nearly impassable unless you have a land rover--to the mines, often several hours from the nearest true village.  It is always an adventure just getting there: from the 25+ hours of flights and layovers, to visa checks and border crossings, then the travel to the mines themselves.  But, mostly, my fondest memories revolve around the people: the miners and dealers in the mining regions.  Warm welcomes of “Karibu”, handshakes, stories, and shared meals.  And of course, the rough gems themselves, sometimes spread out on a tarp or a rickety folding table, with my scale and gem visor at the ready.   

READ MORE: Birthstones Guide, Opal for those born in October

Q. How do you strive to support communities and empower female miners and why is this important to you. 

ANZA Gems is founded on the premise that 10% of sales is reinvested back into the East African gemstone mining communities for education and training.  We officially launched in 2015, and have since sold finished jewellery and gemstones, so we are actively reinvesting back into communities there.  We make trips to Tanzania and Kenya at least a couple of times a year to buy more gemstones, which puts money back into their economy, and check on the schools we support.  There is a primary school near a ruby mine in Tanzania that has been adopted by some in the gemstone industry.  The 450-500 students are mostly Maasai, and there is no shortage of needs: providing hot lunch, bringing books and building a dedicated library that will also serve the local Maasai community, soccer cleats, and teacher housing.  It is always a high point in our trips to go visit the kids and see how everyone is doing. 

Image credit: Monica Stephenson

Another area of investment for ANZA is trade education.  There are a couple of lapidary schools in Arusha, Tanzania, but not a lot of jobs once students graduate.  I am working on setting up the most promising faceting students with modern equipment and more specialised training so that they can make a good living by cutting gems that US, UK, and European markets might embrace. 
And increasingly, I am working on initiatives that involve supporting women miners.  We are hoping to work with an NGO in Tanzania to identify women miners in the Tanga region, to try and bring their gems to market in a traceable way.  It would incorporate the ANZA model of reinvesting a premium back into the women and their villages: equipment, gemmological training, helping the local schools, even local health clinics.  Supporting these women by bringing their gems to market has become a huge priority for me, as well as finding ways to support other women-owned endeavours, from photographers to designers, to the Maasai women who make the ANZA packaging...it’s where I want to go. 

READ MORE: Heritage Series, Basil Anderson

Q. Issues of responsibility in the gemstone sector are always changing, with lots of opinions. What are your thoughts and what more needs to be done?

Whew. There is a huge continuum in the responsible gemstone sector, from “it is impossible to be responsible/transparent with artisanally-mined gemstones” to “look at how ethical we are as a company” to everything in between. The reality is that being responsible and making decisions that positively affect the people and the environment in gemstone mining communities takes hard work, and a commitment to something other than just a financial bottom line.  It’s going to take an attitude of investment in our industry at all levels to do the right thing.  But we must do this.  It’s the only way to ensure consumer confidence in jewellery, and to ensure our future. 

If you would like to join us in London this November and hear our expert speakers click here and register for the Gem-A Conference 2018.

If you are a Gem-A Member or Student you will have received an email to book member or student rates, if you haven't received it please contact membership@gem-a.com.

Cover Image: Monica Stephenson.  


Don't Miss the Summer 2019 Issue of Gems&Jewellery!

Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online. 

Read more


Breaking down the Misunderstandings about Precious Coral

Breaking down the Misunderstandings about Precious Coral

Inspired by Pantone’s ‘Color of the Year 2019’, Rui Galopim de Carvalho FGA DGA dives into the underwater world of precious coral and addresses some of the misunderstandings around its use in the jewellery industry.

Read more


Additional Info

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Investigating Fake Rough with Gem Testing Laboratory Jaipur

From the Summer 2018 issue of Gems&Jewellery, Gagan Choudhary FGA, deputy director of Gem Testing Laboratory Jaipur, describes the various types of fake gem rough that has passed his desk in recent months, including mica rock presented as emerald rough, cubic zircona and topaz fashioned as diamond octahedtrons, and synthetic quartz mimicking aquamarine.

Reaching directly to the miners for procuring rough has always been profitable, but involves a huge amount of risk unless one has enough experience in buying at the source, deep knowledge about the stone being purchased, and handling the pressure thereof.

Often, there have been cases when dealers tend to forget the possibilities of scams and frauds at mining sites or the markets nearby. The sellers at such locations often present glass, synthetics, treated gems or other cheap natural materials as expensive gems in order to make some quick money. This practice has been prevalent at most of the major mining regions around the world for decades.

At Gem Testing Laboratory Jaipur, we routinely encounter such cases, some of which are presented here:

GLASS-FILLED MICA-ROCK, PRESENTED AS EMERALD ROUGH

Recently, a 1,075 gm black micaceous rock was presented for identification (1), a true example of a fraudulent rough, which, although not shocking to us, was definitely an interesting one. Initial observations with unaided eyes from different angles suggested the presence of several crystals, with hexagonal profile, embedded in the rock.

Such rock formation is a common sight for those dealing in emerald rough, especially from locations where emerald is associated with mica (phlogopite) schist, such as Zambia. Careful observation using strong fibre-optic light surprised us. Under reflected light, only small areas or corners of the embedded crystals appeared green.

The rest appeared dark, due to the presence of black mica on and around crystals.

1: This 1075 gm micaceous rock was embedded with elongated ‘hexagonal’ crystals of artificial glass (marked with arrows).
Note the difference of texture around embedded crystals and rest of the rock.

However, when light was transmitted through these crystals, they appeared bright green, which raised suspicion about their origin. Such bright green colour under transmitted light, especially in an embedded crystal, had never been seen before. Further examination revealed a granular texture around these embedded crystals, while the rest of the rock appeared flaky; this supported our suspicion.

These features suggested that micaceous rock was first drilled, filled with green ‘hexagonal’ crystals artificially, and then the joints were covered with a mixture of glue and black mica.

When observed under ultraviolet light,  corners of the embedded crystals (micafree areas) fluoresced chalky-yellow green. Raman analysis confirmed these embedded crystals as artificial glass. 

MICA-COATED GLASS IMITATING EMERALD ROUGH

Another form of emerald-rough imitation are these mica-coated glass (2). In this case, pieces of green glass are first fashioned in the shape of hexagonal rough, which is then coated with fine powder of black mica mixed in glue, followed by a layer of mica chips. These worked-up pieces are then taken to the mining sites by the middlemen and mixed in parcels of low-quality natural emeralds.

The illustrated glass specimens here were seen in a parcel of emeralds from Jharkhand, India.

 2. Glass samples worked-up to imitate emerald rough by fashioning into hexagonal crystals and coating with black mica.
Found mixed in a  parcel of natural emerald. 

SYNTHETIC RUBY FROM MOZAMBIQUE

We came across a small parcel of rough rubies (five pieces, weight range of 3.60- 18.06 ct) submitted for identification. All the specimens were tumbled with a corroded surface and interestingly coated with a yellow-brown substance. Most of the samples were free from inclusions, but under immersion microscopy all displayed curved growth lines, characteristic of synthetic ruby grown by Verneuil process (3).

Appearance of these specimens clearly suggested that they were presented as natural. Prior to this we have seen many more specimens of synthetic ruby, and in much larger sizes, presented as natural. As per the discussion and information from the depositor, these stones were purchased in Mozambique.

3. Rough Samples weighing 3.60-18.06 ct were identified as synthetic ruby. 
note the presence of yellow-brown substance on the extreme right, imitating mud on natural rough

NATURAL AND SYNTHETIC RUBY COMPOSITE

This 28.73 ct bright red rough, associated with some black and white minerals, was presented as a natural ruby. Upon initial examination with unaided eyes, the surface displayed some areas of milky angular zones against a pinkish to purplish background, typically seen in natural ruby crystals.

When examined under transmitted light, a large central area of the specimen appeared bright red, while the edges appeared dark and opaque (4). This raised suspicion about the origin of this rough.

Careful examination under the microscope revealed a sudden change. of growth and inclusion patterns, not only in the core and surface, but also within the surface; the surface displayed small chips with different inclusion patterns.

In addition, distinct colour variation between the core and edges of the specimen was evident. These features suggested that the specimen is a composite where a transparent piece of synthetic ruby is covered with small chips of natural ruby.


4.This bright purplish red-pink rough(top) is a composite of synthetic and natural ruby. The central part is a synthetic ruby while the out part is composed of chips of natural ruby.
Under transmitted light (bottom) the central synthetic part of the specimen appeared bright red, while the edges appeared dark and opaque.

SYNTHETIC SAPPHIRE, PRESENTED AS NATURAL ROUGH

Synthetic counterpart is a common imitation for natural sapphire rough; these are presented in two forms — one as broken, tumbled rough, and second, as fashioned, well-formed hexagonal-pyramidal crystals with surface markings (cover image). Although, their identification is not challenging in a gem lab, they might pose problems while buying at the mines.

The specimen illustrated in (5) was found mixed in a parcel of sapphires, purchased in Madagascar.

5. These two crystals, weighing 63.93 (left) and 44.66 (right) ct displaying bipyramidal habits and associated white mineral, were submitted as sapphire.
The crystal on left was identified as sapphire, but one on the right as glass.

GLASS AS SAPPHIRE ROUGH

Two blue crystals weighing 63.93 and 44.66 ct, as illustrated in were submitted together. Both crystals displayed bi-pyramidal habits and associated white mineral, typically seen in corundum. Interestingly, there was an obvious difference in colour and transparency of both the crystals; the crystal on the right had much better colour and transparency.

Closer inspection of the bright blue crystal revealed hemispherical cavities on its surface, coloured swirls and numerous gas bubbles — the features associated with glass. The grey-blue crystal (5, left) was proved to be natural sapphire, while crystal habit and associated white mineral (kaolinite) suggested Kashmir as its origin.

CUBIC ZIRCONIA AND TOPAZ AS DIAMOND OCTAHEDRON

Cubic zirconia as diamond imitation, both rough as well as cut, have been in existence for a long time, however, in recent years colourless topaz has become a frequent encounter in diamond imitation, especially in rough form. Image 6 illustrates one such example, where the left specimen is a cubic zirconia while the right one is topaz.

6. Cubic Zirconia (left) topaz (right).

These stones are fashioned as typical crystal forms associated with diamond, here, octahedron; often striations, grooves or triangular markings are created on these fashioned octahedrons, giving them a natural appearing crystal.

In the recent past, this author has encountered some large packets of such created ‘topaz octahedrons’, being presented as diamond.

Separation of cubic zirconia from diamond was easily done on the basis of higher specific gravity, while topaz by its anisotropic optic character. Although identification of these imitations is straightforward, when buying at mines or open markets one has to be careful. 

TREATED QUARTZ AS EMERALD ROUGH

In addition to the glass discussed above, emerald rough is often imitated by coated (7) or dyed quartz.

There have been cases where transparent quartz is painted with green colour and presented as emerald, however, as illustrated in 7 (left), such materials can be separated by crystal form (prism and rhombohedral faces) and horizontal direction of grooves or striations on prism faces.

Another material is the quartzite variety, which is first dyed green, then fashioned as hexagonal crystal shape to imitate emerald; such fashioned crystals are often coated with black mica too.

Even body colour, translucency and absorption spectrum (band at 650 nm) can separate such dyed materials from natural emerald.

 
7. Quartz crystals painted with green colour and coated with black mica are presented as emerald rough.
Also note the horizontal direction of grooves or striations on prism face.

SYNTHETIC QUARTZ AS AQUAMARINE CRYSTAL

This is one of the most unusual materials this author has seen for making a fake crystal — synthetic blue quartz fashioned as an hexagonal crystal of aquamarine (8). The crystal was fashioned into six-sided prisms, with pyramids and basal pinacoids — a crystal form commonly seen in aquamarine.

The crystal also contained a conical-tube with brown epigenetic material (such as iron oxide filling) visible to the unaided eyes. On observing the crystal from different sides, it displayed two parallel planes (seed plate) with colourless area and an attached metal clamp. Such features are often seen in synthetic quartz and other gems grown by hydrothermal process.

When viewed from the top i.e. down the ‘c’ axis, the interfacial angles between the prism faces ruled out the possibility of natural crystal form associated with crystals belonging to hexagonal crystal system, such as beryl.

As per the precision at which the nature operates, opposite sides of prism faces are parallel to each other, while in this case no opposite sides were parallel. Identification of this specimen as synthetic quartz was established on the basis of ‘bull’s eye’ optic figure, seed plate and infra-red spectra.

Such cases remind us of the importance of studying crystallography, not only for the identification of gem rough, but also in the creation of fake rough, which the maker of this fake missed out on.


8. Left: blue specimen presented as aquamarine was a synthetic quartz fashioned into a hexagonal crystal, terminated by pyramidal and pinacoidal faces. Also note the conical tube containing brown epigenetic substance. 
Right: the top view of the synthetic quartz specimen

CONCLUSIONS

Fake rough is an inevitable part of the gem trade, and the scams associated with this are increasing day-by-day. Identification of rough, especially in the field is quite challenging, however, one needs to keep in mind the existence of fake material in local markets or even mines.

Careful inspection of the presented rough before making a buying decision is always advisable, keeping in mind the crystallographic features. ■

All images courtesy of the author.

This article originally appeared in Gems&Jewellery Summer 2018/ Volume 27/ No.2 

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: Synthetics presented as natural rough tumbled sapphire. Image Credit: Gagan Choudhary. 


Don't Miss the Summer 2019 Issue of Gems&Jewellery!

Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online. 

Read more


Breaking down the Misunderstandings about Precious Coral

Breaking down the Misunderstandings about Precious Coral

Inspired by Pantone’s ‘Color of the Year 2019’, Rui Galopim de Carvalho FGA DGA dives into the underwater world of precious coral and addresses some of the misunderstandings around its use in the jewellery industry.

Read more


 

Additional Info

Read more...

Speaker in the Spotlight: Q&A with Victor Tuzlukov

As we count down to the Gem-A Conference 2018, speaker Victor Tuzlukov shares some of his insights into the world of gem-cutting ahead of his presentation on 'Precision' and 'Artistic' cuts. 

Q. What first inspired you to work with gemstones?

I’ve liked stones since from my childhood, when I walked alongside a river and collected rock specimens. But just by chance on one occasion my friend, a jeweller, introduced me to a lady who cut gemstones.

She suggested that I give it try, and I tried. Then I tried some more. And more. That was 20 years ago, but even now I keep that image in my mind: a child walking by the river and collecting stones. Collecting to give them life and bring them to people.

Q. What do you find fascinating about cutting gemstones? 

It is unforgettable feeling, when the first facet starts to shine during polishing... it looks like a window into infinity. And then, one by one, they reveal the pure beauty of nature concentrated in crystal. I still cannot believe that I can do it myself.

Q. What drew you to Thailand, and what is the most rewarding aspect of teaching the 'precision cut' there?

In my opinion, Thailand is centre of gem trading. If you want to bring something to the market, you have to be on the inside. In fact, you need to be in the centre.

Once I realised the 'Precision cut', I tried to share this knowledge with all market players – dealers, cutters, gemmologists and jewellers. It’s not only Thai cutters who I teach, but also students from abroad. One time, I had representatives of six nationalities in one group – seven together with me. It was real united nations of gem-cutting! 

Q. Your book Philosophical Stone explores gemstones and symbolic designs with parables. Could you tell us more about how philosophy influences your work faceting gemstones? 

Well, this collection was significant for me. My world viewing is quite metaphysical, and that’s how, from an orthodox family, I came to Buddhist philosophy.

I am sure that if a creative person has something to say to people, he can choose any instrument for this: writing, painting, singing, music or gem-cutting. My stones are just keys: a means to think about our way in life, our soul and our interaction with each other.

To this end, I try to join my mind with the gemstone when cutting. I try to explain to the stone that I also cut myself while gem-cutting, and it is part of our joint journey to perfection.

Q. What is the one thing you’d like the 2018 delegates to take from your presentations at the Gem-A Conference?

The main thing I want to bring is that we are now at the cusp of change in the gem markets. Tomorrow, the precision cut can establish new quality standards for gem-cutting, and the art of faceting can provide a new approach to the evaluation of gemstones as well.

Q. What are you most looking forward to when you visit London this November?

Maybe you know, I am starting new project in artistic cut, which was announced recently. I've cut the first stones of a big collection named “The Heritage”, where each stone is devoted to a specific culture – from ancient ages to nowadays – and it contains sacred symbols and traditional ornaments. This is the project of my life, because it is bigger than my life, and the world's cultural heritage is bottomless. 

This will be my first time in the UK and I hope to take some spirit of the old Great British culture as an inspiration for my work on this new project.

About Victor Tuzlukov

Victor Tuzlukov was born in 1964 in Siberia and lived in Russia. The range of his interests is very diverse – travelling, photography, sport, and literature. His philosophical tales were awarded at the international literary contest “The Golden Feather of Russia”. Victor began to facet gemstones on 1998 and took part in many technical faceting competitions. He is Grandmaster of the US Faceters Guild and winner of the International Faceting Championship in Australia with new world record – 299,17 points from 300. 

Victor has graduated from Moscow branch of the GIA with the diploma of Graduate Gemologist. He is gemstone artist, author of new direction in gem-cutting – “Philosophical Stone”, where gemstones with symbolic design accompanied with parables, disclosing some philosophical conceptions. Now Victor works in Thailand, teaches precision cut and collaborates with jewellery companies and gemological institutes in gem design and grading of cut-quality.      

If you would like to join us in London this November and hear our expert speakers click here and register for the Gem-A Conference 2018.

If you are a Gem-A Member or Student you will have received an email to book member or student rates, if you haven't received it please contact membership@gem-a.com.

Cover Image: Victor Tuzlukov.  


Don't Miss the Summer 2019 Issue of Gems&Jewellery!

Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online. 

Read more


Breaking down the Misunderstandings about Precious Coral

Breaking down the Misunderstandings about Precious Coral

Inspired by Pantone’s ‘Color of the Year 2019’, Rui Galopim de Carvalho FGA DGA dives into the underwater world of precious coral and addresses some of the misunderstandings around its use in the jewellery industry.

Read more


Additional Info

Read more...

Speaker in the Spotlight: Q&A with Dr. Jeffrey E. Post

With the Gem-A Conference 2018 only days away, we speak to Dr. Jeffrey E. Post ahead of his presentation on the Hope diamond. 

Q. What first fascinated you about minerals and led to a life of researching their properties?

My Mother said I picked up rocks, even as a toddler, but I was hooked when my 4th grade teacher showed me a large quartz crystal.  I had never seen anything like it, and I was fascinated.  I knew then that I wanted to study minerals and crystals. 

READ MORE: Heritage Series, Eric Bruton

Q. Do you have a favourite mineral?

It changes every day; I have never met a mineral I didn't love.   

Q. As an established specialist in mineralogy, gemmology and crystallography (to name but a few!), have you noticed any trends over the last decade that have particularly impacted research and the gemstone industry? 

The tools we have to study these materials have dramatically improved and can be applied to smaller and smaller specimens.  We can learn so much more now about a single gemstone, and there is the expectation that we will do so. 

READ MORE: Speaker in the Spotlight, Peter Lyckberg

Q. Your recent publication explored Chameleon Diamonds, what led you to your most recent exploration of luminescence and colour change?

I have long had a fascination with natural coloured diamonds, and those that change colour almost seem magical.  When people ask "how do they do that?" I want to be able to explain the science behind the colour change.  For a material that is nominally simple, diamonds exhibit so many interesting properties.  It is great fun to poke and prod them to learn their secrets. 

Q. As we eagerly anticipate your talk at the 2018 Gem-A Conference, what are you most looking forward to when you visit London this November? 

The opportunity to connect up with colleagues and friends at the conference, and hopefully spend some time at your wonderful Natural History Museum. 

READ MORE: Journal Digest, Amethyst from Rwanda

About Dr. Post

Dr. Jeffrey Edward Post, a native of Wisconsin, received Bachelor of Science degrees in geology and chemistry from the University of Wisconsin - Platteville, and his PhD in chemistry, specialising in geochemistry, from Arizona State University.  Prior to joining the Department of Mineral Sciences at the Smithsonian Institution in 1984, he was a Postdoctoral Research Fellow for three years in the Department of Geological Sciences at Harvard University.  He is currently Chairman of the Department of Mineral Sciences, and since 1991 has served as Curator of the U.S. National Gem and Mineral Collection. Dr. Post served as the lead Curator for the Janet Annenberg Hooker Hall of Geology, Gems and Minerals that opened in 1997. His areas of research interest include mineralogy, gemmology, geochemistry, crystallography, and electron microscopy.  He has published more than 90 scientific articles in these fields.  He is the author of 'The National Gem Collection'.

If you are a Gem-A Member or Student you will have received an email to book member or student rates, if you haven't received it please contact membership@gem-a.com.

Cover Image: Dr. Jeffrey E Post.  


Don't Miss the Summer 2019 Issue of Gems&Jewellery!

Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online. 

Read more


Breaking down the Misunderstandings about Precious Coral

Breaking down the Misunderstandings about Precious Coral

Inspired by Pantone’s ‘Color of the Year 2019’, Rui Galopim de Carvalho FGA DGA dives into the underwater world of precious coral and addresses some of the misunderstandings around its use in the jewellery industry.

Read more


Additional Info

Read more...

Interview: Steve Moriarty on a Lifetime in Gems

From the Summer 2018 issue of Gems&Jewellery, Gem-A Associate Member and co-owner of Moriarty's Gem Arts, Steve Moriarty, shares his fascinating career in gemmology.

Although a gem specialist’s career can often start confined to a classroom or a lab, pouring over stone samples and peering through a microscope, our industry also offers wonderful opportunities to travel around the globe.

Steve Moriarty is not only the co-owner of Moriarty’s Gem Art in Crown Point, Indiana, but also an experienced gem-cutter and gem explorer. His family-run business, including the websitesmoregems.com, tanzanitejewelrydesigns.com, opallust.com and mothersfamilyrings.com, was founded in 1975, and today Steve, his wife Nancy, and two of their three children work together to offer a gem-orientated retail experience. Add to this Steve’s 25-years as a professional gem-cutter and it is clear that he has seen, worked with and sold some incredible gemstones.

READ MORE: Journal Digest, Blue Zircon

“Ever since I was young, I collected rocks and fossils,” Moriarty comments. “I really got interested in the gem business while I was in college; my brother Tom started importing gems from India and would send me stones, which I took to the jewellery arts classes to sell.”

Despite a stint as a chemist, Moriarty opted to follow his passion for gems and in 1975 he joined his brother selling coloured gems to jewellers in the Midwest United States. In these early years, Moriarty says that “colour was not important to most jewellers,” which made businesses like his rare in the region. “My wife Nancy and I started on our own as Moriarty Gem Corporation in 1984 and I began travelling overseas to Thailand for cut gems.” By 1994, with his passion for travelling, buying gems and selling them to retailers waning, Moriarty established his own retail store – now Moriarty’s Gem Art – in Crown Point, Indiana.

A rough garnet and its cut and polished counterpart. Image Courtesy of Steve Moriarty and Moriarty's Gem Arts.

He says: “Cutting gems, creating jewellery, custom orders and four websites is almost more than we can handle at times! I love to cut gems, this is my first priority. But to sell enough of those gems you need to do something with them, and many of the gems end up [as] unique shapes, so most everything is a custom piece. The greatest difficulty my designers and I have is we want to be artists and create our vision, but most often we have to recreate the customer’s vision, or what they saw on Pinterest or somewhere else online.”

READ MORE: Heritage Series -Maggie Campbell Pedersen FGA ABIPP

Despite this, the frustrated gem artist in Moriarty is usually restored by incredible finds and far-flung travels. When asked to describe his most inspiring trips, Moriarty points to the early 1980s, when a trip to Kenya revealed that the border to Tanzania had just been opened to American tourists. “The next day we were off on the five hour bus ride from Nairobi to Arusha, and my love of tanzanite began,” he says.

On a later trip in the early 2000s, Moriarty and his long-time travelling colleague, Jim Fiebig, discovered an “amazing cornucopia of gems” in Madagascar. He says: “There was so much amazing material that we were rejecting great gems just because they were priced a little high compared to the abundant bargains we were getting. I had many great trips to Madagascar after that, buying many of the finest quality gems I have ever owned, but never again in such quantity as the first trip.”

Today, Moriarty focuses his freeform carving attentions on Ethiopian opal, which can “require up to two full days to get a decent polish” because of the undulating surfaces.

READ MORE: Investigating Fake Rough

In addition, Rwandan amethyst, carved by Moriarty, recently appeared on the cover of Gem-A’s The Journal of Gemmology (Vol.36 No.1). Although amethyst is not high on Moriarty’s carving ‘wish list’, this material was particularly impressive. “I had been cutting Uruguay material for 20 years and considered it to be amongst the finest in the world, but when I saw the intensity of the secondary red and blues [in the Rwandan amethyst], I was hooked.”

Moriarty also mentions daylight fluorescent hyalite opal from Zacatecas, Mexico — another find that truly inspired him. After discovering some specimens at the Denver Gem & Mineral Show, he returned home and ended up cutting 7.27 carats — one of the largest faceted opals of this type. “We posted our video on YouTube just before we went to Tucson and someone shared it on reddit.com. In three days, it had been viewed over a million times. Currently, total viewing is over three million.”


Left: Hyalite opal from Zacatecas, Mexico, fluorescing in the daylight. Right: the same opal under UV light.

He continues: “I spent some time looking for hyalite opal to compare pricing, but was unsuccessful finding any cut stones in Tucson 2018. One dealer who specialises in rare gems, did give me an idea of the price [as he had] sold one of five carats. This led me to immediately call my office and have them put the hyalite in the safe and take it offline. It seems this material, discovered in 2013, was mined out by 2016 and was very unique for its characteristic of daylight fluorescence. Our next call was to the dealer who sold me the rough and we met and purchased anything of quality that he had left.”

READ MORE: Heritage Series - Let's Bragg About It!

There is an excitement to this lifestyle, of chasing down gems, that is particularly appealing to those getting started in the field. However, Moriarty also enjoys cutting his ‘old favourites’. He explains: “I love cutting garnets and although the prices for garnets of unusual colours have gone up dramatically, I still think they are under-valued. When I get done with a garnet, to me, it looks as good as any diamond I have ever seen.”


Moriarty mining for sapphires on a trip to Illakaka, Madagascar.

Despite his love of travelling, Moriarty is enjoying the fact that his latest obsession – Oregon sunstone – is much closer to home. And who can blame him for wanting a little more time? After all, there are gems to cut, custom orders to fulfil and a wealth of websites to be cared for… it is all in a day’s work for the Moriarty family. ■

All images courtesy of the author.

This article originally appeared in Gems&Jewellery Summer 2018/ Volume 27/ No.2 

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: Cover of Gems&Jewellery Summer 2018. Image Credit: Gem-A. 


Don't Miss the Summer 2019 Issue of Gems&Jewellery!

Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online. 

Read more


Breaking down the Misunderstandings about Precious Coral

Breaking down the Misunderstandings about Precious Coral

Inspired by Pantone’s ‘Color of the Year 2019’, Rui Galopim de Carvalho FGA DGA dives into the underwater world of precious coral and addresses some of the misunderstandings around its use in the jewellery industry.

Read more


 

Additional Info

Read more...

Retail Focus: Exploring the Emeralds of Colombia

From the Summer 2018 issue of Gems&Jewellery, Gem-A gemmology tutor Beth West FGA DGA EG explores the Musica people and the emeralds of Colombia. 

There is a brooch displayed at the heart of the Geology, Gems and Minerals Gallery in the Smithsonian Institution in Washington, USA.

It is centred on a large luminous green emerald surrounded by diamonds as sharp as stars. It is undoubtedly beautiful; designed by Tiffany & Co. in the 1950s, it evokes an era of glamour and grace. But as exceptional a piece of design as it may be, the brooch is little more than a throne for the emerald that it carries.

The Hooker Emerald, named after the Institution’s principal benefactor, Janet Annenberg Hooker, weighs 75.47 carats and was originally extracted from present-day Colombia in the 16th century, when talk of the majesty of these gems had only just begun to travel.

Emerald, Composite Soude, Image Credit: Gem-A

READ MORE: Steve Moriarty on a Lifetime in Gems

The Spanish Conquistadors arrived in the ‘New World’ in the last decade of the 15th century.

When Hernan Cortez was presented with emeralds by the Aztec Emperor Montezuma II in 1519, the allure of the green gem incited the greed of the invaders and a bid to uncover their source was advanced, often leading to violence and the ultimate mistreatment of the indigenous tribes.

While emeralds became symbols of status and wealth at the end of the trade route set up by the Spanish to India and Europe, what did these stones mean to the original inhabitants of the luscious and majestic Andean terrain?

The first of the tribes’ emerald deposits was located by Conquistador, Gonzalo Jimenez de Queseda in 1537 in the village of Somondoco – home to the Muisca (or Chibcha) people.

This deposit would come to be known as ‘Chivor’, meaning ‘our farm fields, our mother’ or ‘green and rich land’ in the native tongue of the Chibcha, a reference to the emeralds un-earthed there.

Lush Colombian Landscape. Image Credit: Pixabay.com

The Muisca people were one of the four principal civilisations of the Americas.

The other three, the Incas, the Mayans and the Aztecs are perhaps more prevalent in Western thought due to the grandeur and ceremony of the architecture that remains as evidence of their complex culture.

But the Muiscas were no less advanced; they were a self-sufficient people existing in comparative isolation in the highlands of the Cordillera Oriental of the Northern Andes.

It is in this Eastern chain of peaks that pockets of the finest emeralds had formed.

READ MORE: Journal Digest, Blue Zircon from Cambodia

The abundance of the precious mineral within the Muisca’s territory, and the ability of the people to mine it efficiently, made it an important economic resource.

Markets were held regularly in conjunction with calendared festivals during which the Muisca would trade the emeralds with gold from the Guane people from north of the Chicamocha River, yopo (a hallucigenic snuff), exotic feathers and jaguar skins from the lowlands, marine snail shells, avocados and the still celebrated ‘ice-cream bean’ from their coastal cousins, the Tairona people.

Emerald in Matrix. Photo Credit: Henry Mesa. 

There is no evidence to suggest that emeralds were ranked higher in value than the other traded goods, but it is apparent that the stone held substantial symbolic weight.

In 1637, the writer Juan Rodriguez Freyle documented an initiation ceremony performed by the Muisca. On the event of a ruler’s death, the successor would be covered with a fine dusting of gold and placed on a raft at the centre of Lake Guatavita.

As music and dancing defined the shores, the new leader would throw gold and emerald votives into the lake as offerings to the Sun God.

This became known as the myth of El Dorado and rumours of a place saturated with such potential material wealth have been, from the time of its discovery to the present day, exploited by the greed of Western adventurers.

This imposition of material desire on the lands of the natives has ultimately led to wars and bloodshed over the centuries.


Emerald in Matrix. Photo Credit: Henry Mesa.

Therefore, is it perhaps worth considering the stance of the Muisca, who did not covet the emerald as their own but accepted it as a spectacular gift from the mountains, and one that they would happily relinquish to maintain harmony with the gods.

If we were to eliminate the profitability of the gem, could we too be able to see deeper into that mesmerising green? Idealistic? Perhaps. I cannot see anyone throwing the Hooker emerald into a lake any time soon. ■

This article originally appeared in Gems&Jewellery Summer 2018/ Volume 27/ No.2 

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

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Cover Image: Emerald with Quartz. Image Credit: Henry Mesa.  


Don't Miss the Summer 2019 Issue of Gems&Jewellery!

Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online. 

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Breaking down the Misunderstandings about Precious Coral

Breaking down the Misunderstandings about Precious Coral

Inspired by Pantone’s ‘Color of the Year 2019’, Rui Galopim de Carvalho FGA DGA dives into the underwater world of precious coral and addresses some of the misunderstandings around its use in the jewellery industry.

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Buying Guide: Coloured Diamonds from Least to Most Valuable

The typical image of a diamond tends to be of a clear and colourless stone, therefore it is hardly surprising that these are presumed to have the highest monetary value. In reality, diamonds can present as a range of different colours and uniquely-coloured diamonds can command premium prices.

Coloured diamonds are created when impurities or deformities occur in a diamond’s lattice of carbon atoms, with particular impurities resulting in different colour formations.

The most valuable stones will be those which are purest in colour, most saturated and most even in tone. In order to assess the grades of colour, coloured diamonds are placed into one of nine categories: faint (least valuable), very light, light, fancy light, fancy, fancy dark, fancy intense, fancy deep and fancy vivid (the rarest and most expensive).

The Aurora Pyramid of Hope collection polished diamondsThe Aurora Pyramid of Hope Collection contains the full spectrum of natural diamond colours.
Image copyright Trustees of NHM, London.

Increasing rarity leads to higher retail prices and by examining the variations between some notable types of coloured diamonds, we can see a clear scale of value emerging based on an agreed-upon grading system.

Brown Diamonds

The colouration of brown diamonds is caused by a deformation of the diamond lattice during the gemstone’s growth within or expulsion from the mantle. In fact, 98% of all mined diamonds will have a brown tone, which is generally considered unfavourable. However, thanks to the savvy marketing team at Australia’s Argyle mine, a new trend for ‘cognac’ or ‘champagne’ diamonds emerged in the 1990s.

A 1.27 carat fancy intense pink diamond18k white gold ring featuring a 0.26 carat fancy deep yellow orange diamond, a 0.30 carat fancy deep yellow diamond and a 0.53 carat fancy pinkish brown diamond. Image courtesy of BD Luxury: bdluxury.com

Yellow Diamonds

Yellow diamonds gain their colour through nitrogen (N) impurities in the diamond lattice. N often finds itself incorporated in the diamond’s atomic structure, as it is similar in size to the carbon atom. If the diamond has been resident in the mantle for a considerable amount of time, the N will aggregate to form a group of three N atoms and a vacancy. This creates a ‘colour centre’ that absorbs light and makes a diamond appear yellow.

Read more: What Makes a Gemstone Rare?

However, the rarest yellow diamonds are the youngest diamonds; in such stones, the N atoms have not joined forces and remain isolated within the diamond’s atomic structure, resulting in the creation of the celebrated ‘canary yellow’. In May 2014 the Graff Vivid Yellow, at a stellar 100.09 carats, brought $16.3 million at Sotheby's.

Pink Diamonds

Similar to brown diamonds, the pink colouration of a diamond is associated with a deformation of the diamond lattice. This would have occurred while it grew deep within the earth’s mantle in areas where tectonic plates collided and mountains formed.

A 1.27 carat fancy intense pink diamondA 1.27 carat fancy intense pink diamond surrounded by eight Argyle fancy intense pink marquise-cut diamonds and 3.36 carats of pear-shape diamonds. Image courtesy of BD Luxury: bdluxury.com

Read more: Discover the Pink Diamonds of the 2018 Argyle Diamond Tender

The Argyle mine in Australia is one of the principal sources for pinks – but they are rare, accounting for only 0.1% of overall production. Testament to its huge popularity, the 18.96ct Winston Pink Legacy diamond fetched a sum of $50,375,000 at Christies in 2018.

Blue Diamonds

The rarest and most sought-after blue diamonds owe their colour to infinitesimal levels of boron impurities and, like canary yellow, account for less than 1% of all natural stones.

Read more: The 6.16 carat Farnese Blue Diamond

Selling for $57,500,000 at Christies in May 2016, the 14.6ct Oppenheimer Blue is the most expensive fancy vivid blue diamond sold to date, and clearly demonstrates that quality blue diamonds can attract premium prices at auction.

Blue diamondAn exceptional 29.6 carat blue diamond recovered at the Cullinan mine, January 2014. Courtesy of Petra Diamonds.

Green Diamonds

The green colouration in diamonds is generally caused by irradiation and the colour is often only skin deep, having occurred in the crust after the gemstone has formed. A natural green diamond of good colour is very rare and highly valuable; the most expensive green diamond ever sold was the 5.03ct Aurora Green for HK $16.8 million at Christie’s in May 2016. However, because it is very difficult to differentiate between natural and artificially irradiated stones, they are treated with caution by the market.

Dresdner Grüner Diamant Neues Grünes Gewölbe DresdenThe Dresden Green Diamond - a 41 carats (8.2 g) natural green diamond, which probably originated in the Kollur mine in the state of Andhra Pradesh in India. Here it is pictured as part of a hat clasp ornament. (By ubahnverleih - Own work, CC0)

Red Diamonds

Red diamonds are somewhat mysterious to researchers, as the cause of their colouration remains yet unknown. Moreover, as only a handful of stones are known, they remain the holy grail of natural coloured diamonds; the largest ever red diamond, the 5.11ct Moussaieff Red diamond, was discovered in Brazil in 1990 and bought by Moussaieff Jewellers in the early 2000s for an estimated $8,000,000.

Other Notable Coloured Diamonds

There are several other varieties of coloured diamonds, however because of their rarity and the fact that they are mostly sold at tender, it is difficult to place a value on them. One interesting example is the chameleon diamond, a diamond which changes colour when exposed to extreme heat or UV light, which is exceedingly unusual but seldom comes to market. 

Read more: The Geology of Diamonds

Grey diamonds gain their colour through hydrogen impurities. Although they are extremely rare, the very fact that they are so unusual means that they have not attracted a great deal of public awareness and have no substantial market desirability. Likewise, violet diamonds are exceptionally rare and hard to value. One of the oldest types of diamonds (type 1 AB), they typically only appear in sizes up to a maximum of 0.25ct and as such larger stones make particularly special finds.

Argyle Isla 1.14 carat radiant shaped Fancy Red Rio Tinto Gem A BlogThe Argyle Isla - a 1.14 carat radiant shaped fancy red diamond. Image courtesy of Rio Tinto. 

As with red diamonds, orange diamonds are very unusual and the origination of their colour has not yet been discovered. The largest ever orange diamond, a 14.82ct pear-shaped fancy vivid orange, stunned at Christie’s in 2013 when it sold for CHF 32,645,000, over double its lower estimate.

By contrast, although white (not clear, but diamonds with a milky-white tone) and black diamonds are quite rare, they have not managed to capture the favour and attention of the public and are considered to be the least valuable of all coloured diamonds.

Interested in furthering your knowledge about diamonds? Find out about Gem-A's Diamond Diploma and Workshops here.

Cover image: Fancy colour diamonds from the Aurora Pyramid of Hope collection - rough and polished diamonds. Copyright Aurora Gems. Photo by Robert Weldon.

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How to Identify Antique Edwardian Jewellery

Understanding how to identify jewellery from different eras and design movements is essential for historians, valuers and antique collectors. Here, Starla Turner FGA GG offers us a glimpse into the refined and elegant world of Edwardian jewellery and describes the motifs that make pieces recognisable. 

The short reign of King Edward VII (1901 to 1910), his court, his sporting lifestyle and his wife Alexandra of Denmark were a breath of fresh air to fashion at the close of the 1800s. Jewellery motifs changed accordingly, with intricate and gracefully symmetrical, diamond-encrusted and lacy designs adorning the neckline, chiffon gowns and the ‘up-do’ hair styles of the well-to-do. Delicate scrolls, leaves, ribbon bows, hearts, circles, swooping swags (or garlands as they were later called), and veil-like twinkling jewellery complimented a new sophisticated style.

To me, Edwardian designs look like a frozen moment – curled in movement, shimmering, draping, scrolling, swaging, circling – just waiting to be worn and move again. The Edwardian femininity, fluidity, and fineness are unmistakeable. Iconic pieces have hinges, dangles, swags, articulation, and tiny swinging gemstone droplets evoking a liquidity and liveliness.

Queen Alexandra loved the uncomfortable but fashionable ‘dog collar’ plaque style necklace, often backed by black velvet. The style transitioned into a column of 6-16 rows of pearls — a challenge to wear for sure. Changing dress necklines brought changing neck ornamentation. A good example is the rivière necklace – a neck-encircling strand of graduating, millegraine-edged, bezel set diamonds — sometimes worn as two bracelets.

Read more: The Tale of the Mouawad-Tereschenko Blue Diamond

We see up to 72-inch long strands of ‘spectacle set’ diamonds, a minimalist technique where only a thin wire wraps the diamond girdle and small side jump rings attach to the next gem. The lavaliere is an articulating drop suspended from a matching design element and attached directly to a thin, fancy link chain. The negligee necklace has two drops, often on different lengths of chain, attached to one design element and a simple chain. Basic pendants have diamond-set, double side engraved, tapered bales that hang on thin, intricately designed chains.

The Edwardian era also saw a fascination with tiaras. Bandeaus, like tiaras, could double as necklaces or bracelets — screw holes or extra loops in the backside show their transitioning versatility. Sautoirs, long bundles of pearl strands ending with tassels, were wrapped around necks, waists, bodices and arms. Bracelets show symmetrical repeating designs in either full length or top half only designs. A new trend was the more diminutive, tapering diamond and coloured stone bracelets with articulating or stretching metal links in the rear. Rings were becoming wider and domed just enough to accommodate the depth of the centre diamond.

Edwardian Swan Brooch Back by Lang Antiques Gem A Blog Antique Jewellery VintageThe back of a beautiful swan pin, showing calibré cut emeralds and the 'swinging' diamonds typical of the Edwardian era. 

Solid platinum or platinum over gold suited the pale, pastel and feminine fashion palette. Platinum was a new white metal that, unlike silver, didn’t stain the skin and clothing and could strongly, but delicately, hold the all-important diamond. Initially, platinum was bonded to yellow gold, a technique created to add value and acceptability to this new, inexpensive and unappreciated metal.

The vast majority of Edwardian diamond pieces I see are hand-fabricated (cut, sawn, rolled, drawn and assembled). Cast pieces are uncommon due to the high heat required to melt the metal. Edwardian jewellery is typically assembled from fewer parts, likely due to the visibility of the yellow gold-based solder that was used.

Read more: A Quick Guide to the British Crown Jewels 

This yellowish solder in seams disappeared into a whiter hue after WWI when white gold made its debut. In addition, platinum is a noble metal – it does not tarnish – so the tarnish one sees is from the solder mix of gold, silver and platinum. Therefore, tarnish and patina can add provenance as it develops with age. Sometimes re-polishing the metal can remove a bit of authenticity.

South Africa supplied a plethora of diamonds. While the Second Boer War (Oct 1899 –May 1902) had an impact on pricing, the demand continued. The diamond circular saw, the fixed dop (the clamp that holds a diamond being cut) for precise angles, bruiting machine advancements and electricity reduced cutting times. They also resulted in the more brilliant, rounder European-cut diamond. Marquise and pear-shapes also became more available. The beauty of a finished diamond became the focus, rather than the weight retention.

Edwardian Brooch by Lang Antiques Gem A Blog Antique Jewellery VintageAn Edwardian era pin that would have doubled as a tiara or hair ornament. 

Later into the period, single cut diamonds replaced the rose cuts of the past. With faster cutting techniques, the sparkling 17 facet single cut became the perfect accent to delicate jewellery. Smaller Swiss-cut and small European-cut diamonds also help date this era. Old mine cutting was phased out by the end of the era, but diamonds were still recycled into new pieces.

Pearls were second to diamond in popularity and suited the monochromatic styling of the era. Their ethereal sheen worked beautifully with gossamer fabrics. Articulating drops gave the appearance of water and added the wonderful element of movement in open work designs. Due to the rarity of natural pearls (cultured pearls were about to debut in high numbers) seed pearls of 3.5mm or smaller were cut into two useable halves and flush mounted onto metal.

Read more: Understanding Diamond Colours with the Aurora Pyramid of Hope 

The American and Scottish freshwater pearls reveal a whiter, wrinkled skin whereas the Indian Ocean and Gulf saltwater pearls are creamy to light grey (often turning grey from a soap that has been used to clean them) and smooth skinned. Uncut and larger natural pearls are often button or oval shaped. The very round cultured pearls in Edwardian pieces tend to be replacement stones.

Sapphire, emerald, opal, ruby, amethyst, demantoid garnet, moonstone or peridots were recessed into a circle of diamonds — enter the halo ring! Look for treasures in these old pieces: Kashmir sapphires, Burmese rubies, Russian demantoid garnets, Australian black opals.

Edwardian Oval Diamond Brooch by Lang Antiques Gem A Blog Antique Jewellery VintageA pierced-out brooch from the Edwardian era.

Calibré cut stones, the tiny (1-2mm), straight-sided, geometrically shaped ruby, sapphire, emerald and amethyst, were cut to fit into channels and dance around designs. The newly-created and evenly-coloured synthetic sapphire and ruby calibré appear in late Edwardian pieces. Black enamel or onyx also provided contrast to the all white look as it transitioned from the mourning jewellery age.

A platinum and diamond central ornamentation could also be highlighted with a larger splash of colour from background bases of pastel toned, transparent to translucent enamels over an engraved gold base — a technique called ‘guilloche’.

Read more: The Fascinating History of Platinum Jewellery 

Further defining methods of this era are millegraining and fret work. Overall pieces are finished with delicate, minute beading making the metal disappear into the design. This millegraining took away the sharp edges, softening the look and emphasising the diamond sparkle. Millegraining also enhanced the knife-edged, open, thin wire work called fret work (like the frets for chords on a guitar neck) that created the airiness to the designs and highlighted the incredible expertise of the craftsman.

After WWI the flowing movement of the graceful Edwardian jewellery eventually blended into, and was then lost to, the geometrical, static, anticlassical, architectural style of the Art Deco era — that caught on like fire. Out with the old, and in with the new. 

Follow your passion for gemmology with one of our in-house diamond grading and gemstone workshops

This article was originally published in the Spring 2019 issue of Gems&Jewellery. Gem-A Members can read the issue online, here

Cover image: The front of a beautiful swan pin, showing the calibré cut emeralds and the typical swinging diamonds, all set in platinum. All images courtesy of Cole Bybee and Lang Antiques

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Don't Miss the Summer 2019 Issue of Gems&Jewellery!

We are delighted to announce that the Summer 2019 edition of Gems&Jewellery is now available to Gem-A Members and Students in print and online.

Our quarterly magazine includes exciting updates from the world of gemstones and jewellery, interviews and features from industry experts and the latest Gem-A news.

Gem-A CEO Alan Hart kicks off our Summer issue by looking ahead to the annual Gem-A Conference which takes place from 2-3 November at etc.venues County Hall on London’s South Bank and promises to be a fantastic networking and socialising opportunity for gemmological professionals and enthusiasts.

Aerial photograph of the peninsula hosting ruby mineralisation at Aappaluttoq, Greenland. Photo by William Rohtert.

Reflecting on a recent visit to South Africa, Deborah Craig FGA DGA brings us an insight into the difficulties facing the country’s diamond industry on page 10, which is closely followed by a report on the discovery rubies in Greenland by David Turner, William Rohtert, Meghan Ritchie and Brad Wilson, who uncovered the Aappaluttoq ruby deposit in 2005.

Read more: The Geology of Diamonds

Turn to page 18 to see and read about some of the highlights of the Victoria & Albert Museum’s newly reopened William and Judith Bollinger Gallery which include vanity cases from the collection of the late Freddie Mercury, Beyoncé’s Papillion ring by Glenn Spiro and, undoubtedly the stand-out piece of the display, Queen Victoria’s sapphire and diamond coronet.

A selection of moonstones from India where a broad range of material is available in abundance. Photo by Henry Mesa.

On page 26 we report on a visit to Hatton Garden-based gem dealer Marcus McCallum to discover the history, origins and varieties of moonstone, as well as some helpful tips for buying these mythic and much-loved gems. Later, on page 32, professional valuer Shirley Mitchell FGA DGA FIRV reveals her ‘7 Steps to Success’ for accurate jewellery valuation.

Read more: Questions to Ask When Buying a Piece of Gemstone Jewellery

Anyone with a passion for diamonds will not want to miss our feature beginning on page 39 on the scintillating 302.37 Graff Lesedi La Rona, which was cut from the second-largest diamond ever discovered and is undoubtedly one of the most exciting arrivals to the world of gemmology this year.

A large opal with beautiful flashes of blue and green. Photo by Gem-A.

Our 2019 Gems&Jewellery columnist, jewellery historian and valuer John Benjamin FGA DGA FIRV, continues his Gemstone Conversations series with a fascinating column on amethyst, delving into its cultural significance and popularity in jewellery design throughout history. To round off our Summer issue we hear from Gem-A tutor Barbara Kolator FGA DGA and Gem-A operations manager Charles Evans FGA DGA, who share their experiences of an opal grading workshop at Gem-A HQ led by Andrew Cody FGA (Hons), director of Cody Opal.

Read more: Explore the Historic Significance and Mythology of Amethyst

What’s more, this issue contains interesting and insightful pieces ranging from subjects as varied as photomicrography, current developments in Chinese jade carving, and ruby sorting innovations in Mozambique. Whatever your gemmological interest, you’re bound to find something intriguing in this season’s edition of Gems&Jewellery!

Gem-A Members and Students can access a PDF version of Gems&Jewellery here. Simply access the archive with your log-in details. 

Would you like to receive print editions of Gems&Jewellery and The Journal of Gemmology straight to your door? Become a Gem-A Member today.

Do you have an idea for an upcoming Gems&Jewellery feature? Share your thoughts with our editorial team on editor@gem-a.com.

 

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