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Colored diamonds, the focus for Mediterranean Gem And Jewelry Conference

25 may 2017

By Abraham Dayan

Now in its third year, the annual Mediterranean Gem and Jewelry Conference, which this year took place in Syracuse, Sicily in mid-May, provided participants with an opportunity to immerse themselves in the world of colored diamonds and their characteristics.

The aim of the conference was to give an exhaustive review of colored diamonds, as well as to provide workshops on how to grade them. The first day of the May 12-14 event saw an intermediate workshop on the screening and identification of small and melee synthetic diamonds in jewelry, followed by an advanced course on the grading and identification of colored diamonds, both natural and treated.

Meanwhile, the second day of the conference gave attendees the opportunity to hear about specific stones, as well as to receive scientific explanations regarding the composition of colored diamonds. The conference attracted independent lab gemologists, appraisers, gem experts, dealers and jewelers.


On the first day of the event, there was an intermediate level workshop on the screening and identification of small and melee synthetic diamonds in jewelry by Branko Deljanin (CGL-GRS) and George Spyromilios (IGL).

National Colored Diamond Industry Association (NCDIA) President Alan Bronstein started the proceedings on the second day of the conference by recounting the story of the creation of the 12.03-carat Blue Moon diamond from rough to the polished stone which was sold for a world record $48.4 million at Sotheby's in Geneva in 2015. "This stone is regarded as one of the most extraordinary blue diamonds found in recent decades, and certainly one of the most extraordinary that I have ever seen," Bronstein told the audience, as he showed images of the Cullinan mine in South Africa where the blue gem was discovered. The operation was a famous de Beers mine which was sold a decade ago to Petra Diamonds.

Bronstein explained how Cora Diamonds bought the rough stone for more than $26 million, and asked him to provide his opinion on the diamond and how it should be cut. "The company took an incredible risk in buying the diamond for close to $27 million, and I was called in to give an appraisal in case it broke on the wheel during the cutting process," he said. "The process led to the making of 30 plastic models in order to create the right shape and cut. I, along with many others, was asked to give my opinion on how the diamond could be cut. My vision for the diamond and how it should appear was the Hope Diamond in the Smithsonian Institute in Washington DC," he added.

Providing a scientific basis was the next speaker, HRD Antwerp's Chief Education Officer Dr. Katrien De Corte. Her presentation was entitled 'Type II diamonds: good, bad and rare'.

Thomas Gelb spoke on 'Color grading fancy colour diamonds and their relationship to value'. He was followed by John Chapman on 'Colour grading of diamonds by instruments', and then Branko Deljanin delivered a presentation on 'A new approach to grading and certifying coloured diamonds – provenance type'. His CGL-GRS lab in conjunction with GRS lab has started to certify Argyle pink/blue diamonds based on a measurable “fingerprint”.

Kym Hughes, President of the National Council of Jewellery Valuers of Australia and the principal of Symmetry Jewellery Valuation Specialists, spoke about the valuation of colored diamonds for the trade and consumers. With synthetic diamonds always an issue for the industry, Alexey Useinov, from TISNUM on behalf of ALROSA, spoke about the company’s new Diamond Inspector instrument for screening synthetic diamonds.

Illaria Adamo of the Italian Gemmological Institute spoke on the subject of 'Demantoid garnet: identification and origin determination', while Victor Tuzlukov and Alicia Vildolsa from Russia and Spain, respectively, talked about 'The evaluation of artistic cuts for a new generation of gemstones'. Larry French of the Gianmaria Buccellati Foundation, Italy, gave a presentation on working with the great Italian goldsmith and jeweler.

Completing the second day of the conference was a roundtable discussion moderated by John Chapman on 'Colored diamonds – describing and marketing, and the impact of fluorescence on identification and value of diamonds'. A discussion followed among six panelists and more than 70 participants, and most agreed that fluorescence has a positive effect on colored diamonds making them more unique. A survey on fluorescence among participants showed that more study is needed to better understand the impact of fluorescent diamonds on the color grade of near-colorless diamonds, and that these kinds of stones are unfairly penalized when possessing medium to strong fluorescence.

Participants were unanimous in their praise for the organization and content of the conference. Well-known gemologist Antoinette Matlins said it had provided a high level of discussion and debate. Meanwhile, independent gemologist Barbara Dembowski from Poland said the conference had provided her with solid information about colored diamonds and how to grade them.

Branko Deljanin said the conference aimed to provide a European setting for diamond conferences, since the focus of the international trade is usually on the North American and Asian markets.

The conference was organized by IGL (Greece) and CGL-GRS (Canada) in conjunction with CERTILINE (Italy) and supported by the National Association of Jewelry Appraisers (NAJA), MAGI (Italy/Finland), JAW (UK), IGI (Italy), Martin Steinbach (Germany) and Eickhorst (Germany), while the major partner was Russian mining company ALROSA.

Next year's conference will take place in Nice, France.