On May 6th – 9th Valencia in Spain was host to the 2nd Mediterranean Gemmological & Jewellery (MGJ) Conference. This year’s event had the theme of diamond treatments and attracted gemmologists, jewellery appraisers, dealers, retailers and scientists from 20 countries. Among many Spanish jewellers, gemmologists and appraisers we had 9 NAJA appraisers and representatives from international mining companies (Alrosa, Russia, De Beers, UK), diamond processing facility (Suncrest, USA), synthetic diamond producers (Algordanza, Switzerland), major jewellery, appraisers and gem organizations (CIBJO, JAW, ICA) and retailers (Swarovski, Austria). This conference was organized by CGL-GRS lab, Canada and IGL lab, Greece in cooperation with NAJA, USA and MLLOPIS lab, Spain.
The opening address was delivered by Dr Gaetano Cavalieri from CIBJO describing the role of the organisation in protecting consumers as specified in the ‘Blue Book’ series which defines grading standards and nomenclature. Examples were described of fraudulent or misleading conduct by jewellers or traders which have been acted upon by CIBJO. Dr David Fisher from DeBeers Research (UK) was the invited speaker for the conference describing recent research towards understanding colour defects in diamonds, particularly brown, and their response to HPHT processes. This presentation was followed with examples of commercial treatments performed by Suncrest Diamonds (USA) applying HPHT and irradiation treatments to alter the colour of diamonds. Sonny Pope emphasised the opportunities from transforming low value brown diamonds into fancy colours, to rival coloured gems.
The application of HPHT, irradiation and combinations of these treatments to disguise the nature of a diamond was revealed by Dusan Simic (AG&J, USA) in his talk in which he described instances of laboratories reporting ‘natural’ for synthetic or treated specimens. He identified features in FTIR and PL spectra, such as the width of the 741 nm irradiation peaks, as useful indicators of treatment and considered that improving laboratory techniques and interpretations are making instances of mis-identification rarer.
With analytical tools a key for detection, Mikko Astrom from M&A Gemological Instruments (Finland) described the principles and practicalities of infra-red spectroscopy. Examples of features were described for diamonds and coloured stones, including detection of fillers for emerald and amethyst.
Besides treatments, the source origin of purchased gems is another consumer concern. This growing concern was addressed by Jean Claude Michelou (France) – a gem and jewellery expert and policy advisor who highlighted the difficulty in tracing the 17 different species of coloured stones sourced from 47 countries with undeclared or under-declared reports at borders. The importance of source in the value of a gem was illustrated by Jeffrey Bergman from Primagem (Thailand) who showed examples of opals, star sapphires and trapiches and the influence on their value of source origin and visible features. Lisa Elser from Custom Cut Gems (Canada) provided her personal experiences of buying rough gemstones in the field including offerings of synthetics at mine-sites and the tactics of sellers.
The availability of different gems through history as world exploration expanded had a strong influence on jewellery design as revealed during a presentation on Portugese jewellery by Rui Galopin de Carvalho (Portugal) with examples from the royal collection. A significant British royal gem is the Koh-i-noor which was the main topic of a presentation by Alan Hart from the British Museum of Natural History. He traced the history of the stone with casts from the museum’s collection and examined how the polishing anisotropy of diamond had a strong influence on the shape of Mogul-style cuts. Delegates in the audience noted the availability for scientific research of over 1000 diamonds and almost 50,000 gemstones – all untreated.
The final conference session was a ‘round-table’ discussion moderated by John Chapman (Gemetrix, Australia) on the topic of diamond treatments. The discussions explored technologies, detection, and consumer aspects of treatments with the audience contributing their questions and views to a panel comprising experts from various fields. The Round table panellists were Dusan Simic (AG&J), Gail Brett Levine (NAJA), Sonny Pope (Suncrest Diamonds), Mikko Åström (MAGI), Dr Gaetano Cavalieri (CIBJO) and Branko Deljanin (CGL-GRS).
A special feature of the MGJ conferences are diamond workshops. Due to high interest in testing new samples of treated and synthetic diamonds, Extra Day on Advanced Diamond Workshop is added before the conference.
Three workshops (Basic to Advanced) were conducted on natural, treated and synthetic diamonds during which participants put their learnings to test by identifying 50 diamonds samples with the aid of microscopes, UV lamps and cross-polarisers. UV-Vis, Raman and FTIR spectrometers provided by MAGI (Finland, Italy) enabled further testing for complicated treated CVD and natural diamonds. A new ‘PL inspector’ developed by Gemetrix was used for checking fluorescence/phosphorescence reactions and proved a very useful tool to separate natural from synthetic diamonds. This and other portable instruments and books, as well membership to MGJC are available on-line at https://www.gemconference.com/store
A conference dinner completed the weekend while a guided city tour provided visitors with a deeper appreciation of the host city.
The conference and workshop received very positive feedback for its organization, excellent speakers and practical workshops from more than 75 participants and many expressed a desire to come back again.
Next year’s conference is planned for Syracuse, Sicily (Italy), with the theme of coloured diamonds. A detailed program with two new workshops will be announced in September 2016.
Details of the conference series can be found at www.gemconference.com
Branko Deljanin, CGL-GRS, Canada, Conference Chair firstname.lastname@example.org
George Spyromilios, IGL, Hellas, Conference Co-Chair email@example.com
John Chapman, Gemetrix, Australia, Proceedings Editor firstname.lastname@example.org