Day: March 31, 2021

SSEF scientists author first published study of new high-quality emerald type from Afghanistan

BASEL, SWITZERLAND: MARCH 24, 2021 – The first detailed study characterising an emerald type from Afghanistan that has recently become available in the gemstone trade…
Posted in Gemstones, News

BASEL, SWITZERLAND: MARCH 24, 2021 – The first detailed study characterising an emerald type from Afghanistan that has recently become available in the gemstone trade has been prepared by a team of scientists from the Swiss Gemmological Institute SSEF, and published in the most recent edition of Journal of Gemmology. One of the challenges posed by such emeralds is that they are on occasion mislabeled as being Colombian, for they closely match South American specimens not only visually, but also in terms of their gemmological properties.


To conduct the study, the SSEF research team tested and analysed more than 100 gem-quality emeralds from the Panjshir Valley in Afghanistan, ranging in size from 1 carat to more than 30 carats. 

A specimen of the newly available emerald type from Afghanistan (left), pictured alongside an emerald from Colombia. Photo: SSEF


To develop reliable means of distinguishing the Afghan emeralds from others in the marketplace, the research team compared hundreds of emeralds from different origins using a machine learning statistical algorithm (t-SNE: t-distributed stochastic neighbor embedding). Through a compilation of 56 elements in the t-SNE calculation, the emeralds from Afghanistan could be further characterised and differentiated from Colombian samples.


Gemmologically, the research team reported that the new emerald type from Afghanistan is characterised by spiky to tubular fluid inclusions (multiphase) and very fine and parallel hollow channels, both quite similar to inclusion features observed in Colombian emeralds. Although the team occasionally observed some chevron-like growth features, the honeycomb-like pattern (“gota de aceite”) that is characteristic of emeralds from Colombia emeralds has not been observed to date in these new emeralds from Afghanistan.

The chemical composition of these Afghan emeralds is astonishingly similar to Colombian emeralds. Only a careful trace element analysis of the stones revealed differences, with the most frequent being a higher iron concentration in the new-type Afghan samples, when compared to emeralds from Colombia. However, the iron concentration in Afghan materials is still much less than that found in emeralds mined in Zambia, Brazil and Russia, to name a few.


“This research project perfectly shows how the science of gemstone testing is constantly evolving, and we are proud to be at the forefront of such efforts in providing gem labs and the trade with new scientific knowledge about these fascinating new emeralds,” said Dr. Michael Krzemnicki, Director of SSEF and one of the authors of the study.

To download a PDF copy of the report published in the Journal of Gemmology CLICK HERE.

Further reading:
Emeralds and diamonds in Dubai

Singing the blues

Natural blue diamonds are the rarest of the coloured diamonds. Here’s a quick primer to sing the praises of the blues.
Posted in Diamonds

The rarest of the coloured diamonds are the blues. A blue diamond is a natural diamond with a noticeable blue tone to it caused by trace amounts of boron in the crystalline lattice structure. Blue diamonds range in hue from light blue to deep, dark saturated blue with all the shades of violet, grey and green in between.

The blues are completely natural (in gemmology as in mental health) and must be untreated to be considered ‘real’. A ‘real’, natural blue diamond is created in the earth and other diamonds that have been artificially treated to gain their blue tones are not considered real even if they are diamonds. A GIA certificate will describe a real blue diamond as ‘natural’. Treated or enhanced stones attract far lower prices than real blue diamonds and there are different colour tones between the two groups of diamonds.

The same four C’s of diamond connoisseurship govern the value of a blue diamond, but colour is considered the most important. There are no known blue diamonds with a completely flawless (F) clarity rating though those with the highest clarity grades are always the most valuable.

The wide range of colours amongst blue diamonds contributes to the difference in price between the hues with the lighter blues and greys usually out-priced by the more valuable deeper hues. Blue diamonds are considered more beautiful when there is no secondary colour present but instead display a single pure blue colour. These pure blue diamonds are Type IIb diamonds, meaning they contain either very few or a complete lack of nitrogen impurities, but do contain boron within the crystal matrix. A Type Ia blue stone would contain a secondary hue and get its colour from the presence of nitrogen atoms in the carbon lattice. These tend to be more blue-grey in colour and this can be unrelated to boron. Violet diamonds are caused by a combination of crystal lattice distortion and a high hydrogen content. Secondary hues can add tint and character to a stone.

The strength and depth of a diamond’s colour is its colour intensity level. This is graded by the GIA and other laboratories on the Fancy colour scale – a list of 27 colour hues that span the full spectrum for coloured gems and diamonds. For the blues the grading scale includes (but is not limited to) Faint Blue, Very Light Blue, Light Blue, Fancy Light Blue, Fancy Blue, Fancy Intense Blue, Fancy Deep Blue and Fancy Vivid Blue. Fancy Dark is also possible in a stone with secondary colour. The famous Hope Diamond is considered a fancy dark blue diamond.

Much is made of the rarity of the pinks, but the blues are amongst the rarest and most expensive diamonds in the world. Only three locations on the planet have unearthed blue diamonds: India’s historically famous Golconda mine, the Cullinan mine near Pretoria in South Africa and, of course, the Argyle mine in Australia. With the closing of Argyle, this leaves South Africa as the principle source of blue diamonds and the mine there is considered past its peak production capacity. In terms of scarcity, blue diamonds have greater rarity than their pink diamond counterparts, constituting less than 0.004% of global production.

The Argyle Violet. Discovered in 2015 and offered at tender in May 2016, the Argyle Violet was the largest natural violet diamond ever found by Rio Tinto and was described at the time as ‘impossibly rare.’ In the rough, the stone was 9.17 carats and reminiscent of a meteor, with an unusual shape for rough diamonds with deep grooves and an uneven surface. A polishing plane was established over a period of many months, employing a blend of science, technology, experience and art, but in the end, the ultimate challenge of cutting and polishing the stone lay in the careful hands of a single master. The final result was a 2.83-carat diamond with a polished oval shaped cut. The stone was auctioned in 2016 to a New York diamond investor for a never released price estimated to be between USD $3–5 million.

The Argyle diamond mine occasionally unearthed violet diamonds which were dizzyingly beautiful. For every 25 million carats of rough that was produced from Argyle, a single polished blue or violet stone was tendered. In the 37 years of Rio Tinto’s Pink Diamond Tenders, only 42 diamonds held a Blue or Violet GIA grading report.

Further reading:
Three fancy coloured diamonds lead sales at Christie’s

Coloured diamond mining in Australia post-Argyle

The now-closed Argyle mine produced almost 90 percent of Australia’s diamonds, but until five years ago, the Ellendale mine in Western Australia was also a…
Posted in Diamonds

The now-closed Argyle mine produced almost 90 percent of Australia’s diamonds, but until five years ago, the Ellendale mine in Western Australia was also a significant player in the world’s coloured diamond market.

The Ellendale mine was established in the 1970s and once provided half the world’s yellow diamonds with an exclusive arrangement with Tiffany and Co helping bring Australian yellow diamonds to the world stage. But the mine was mothballed five years ago when the operating company was liquidated. After ‘refurbishments’ by the WA government, two Australian companies have pursued exploration leases in the mine area, with the hope of re-establishing a commercial operation.

Yellow diamonds can command between two and four times the price of white diamonds and while they’re not quite in the price range of pinks, they’re scarce and scarcity drives demand.

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The Sputnik Covid Diamond

Pink leads in desirability in fancy lab-grown coloured diamonds

In the last five years, the technology involved in creating coloured diamonds has significantly improved the production and consistency of the resultant lab-grown stones, making…
Posted in Diamonds

In the last five years, the technology involved in creating coloured diamonds has significantly improved the production and consistency of the resultant lab-grown stones, making it possible for even finer colours.

“At this point in time, we’ve seen an increase in demand for pinks, blues, and canaries. We expect to see a lot more fine and fashioned, coloured lab-grown diamond jewellery coming to the market this year,” ALTR Created Diamonds President, Amish Shah said. ALTR is the world’s leading lab-grown diamond producer.

Over the past 12 months, demand for colours has moved into the wider lab-grown coloured diamond category with more designers focused on creating jewellery that explores the opportunities the sector offers.

Currently coloured diamonds account for less than one per cent of the overall lab-grown diamond production but Mr Shah projects that this share will exponentially in the next 12 months.

“The lab grown diamond category offers the consumer an opportunity to wear larger and more beautiful diamonds. Coloured diamonds fall under that aspirational purchase that consumers have always wanted. Price plays a very important role, but the desire of the consumer for beautiful, coloured diamonds is the main driving force,” he said.

In addition, the lab-grown diamond community is focused on being a far more socially and environmentally conscious product and this has been a key driver to the overall category.

ALTR is working towards improving its coloured lab grown diamond offer in various shapes and sizes. More colours are being developed and these will be unveiled in the latter part of 2021.

In 2018, it launched ‘The Pink Rose,’ the world’s largest pink diamond at Borsheim’s in Omaha during the week of the Berkshire Hathaway Shareholder event.

Mr Shah pointed out the company’s strength lies in its variety of traditional and patented cuts. “As a company, we hold 48 patents on special cuts. While cushions lead the category as a shape, fancy coloured ALTR Created Diamonds are available in a variety of traditional cuts on order as well as in patented cuts for custom order,” he said.

He believes the opportunity to rekindle consumer desire for created lab-grown diamonds will expand over the next three years, especially as various design houses create more designs for the space.

“Lab-grown diamonds have opened the opportunity for cutting newer shapes and colours. The trade and consumer will both have an opportunity to explore these newer shapes and fancier colours in jewellery that they have never seen or designed.”

In the fancy lab-grown diamond category, pink leads in desirability across the world. “From the supply perspective, the pink is still the toughest, followed by the blue and canary,” Mr Shah said.

Argyle Pink Diamonds statement ring unveiled in New York
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