Lectures

Dr. Thomas Hainschwang (GGTL Laboratories)
The Colour and Colour Origin of Untreated and Treated Natural and Synthetic Diamonds

While the majority of diamonds are colourless to near-colourless, natural diamonds occur in a large range of natural colours that cover all the hues of the rainbow. This presentation gives an overview of the colours that can be found in natural and synthetic diamonds, the colours that can be created for such diamonds by treatments such as irradiation, annealing and HPHT. The causes of theses colours and the challenge of the identification of their origin will be being discussed.

Dr. Philip Martineau (De Beers Research)
CVD Synthetic Diamonds and Their Detection

For many years De Beers has carried out proactive research to understand the characteristics of different kinds of CVD synthetics that can be produced in order to build robust identification methods that support full disclosure of products. This research has made use of the synthesis expertise of Element Six in proactively challenging identification methods so that they can be improved to cover any potential emerging identification challenges. This talk will describe how this approach led to the development of different generations of screening and detection equipment now sold by IIDGR (the International Institute of Diamond Grading and Research) including the instruments launched this year: AMS2 and SYNTHdetect.

Roman Serov (Octonus/MSU)
Impact of Fluorescence on Diamond Appearance

All previous fluorescence studies were based on subjective estimation of fluorescence influence on diamond color based on subjective human observation. And still in the industry there are many uncertainties and myths related to the fluorescence impact. In our study we developed a device that can create a lighting environments with different levels of UV content corresponding to D65 lighting, Lab lighting, UV free lighting etc. Based on that data objective measurement of fluorescence impact on diamond appearance both for pavilion color (as graded in lab) and table color (as perceived by customer) can be performed.

Branko Deljanin (CGL-GRS Swiss Canadian Gemlab)
John Chapman (Gemetrix)
George Spyromilios (IGL)
ID of Melee to Large Synthetic HPHT Diamonds with Standard Instruments

Over recent years advances in HPHT technology enable growth of colourless high quality diamonds from 0.01 – 15 ct polished. Synthetic melee, mostly HPHT-grown, are produced in China and India and mixed into parcels of natural diamonds. A task of a gemologist/appraiser is to conveniently identify different types of natural diamonds and synthetic diamonds using standard instruments (e.g. portable “Synthetic Diamond ID Kit” ). The use of fluorescence, phosphorescence and cross polarized filters will be described as means to help identify synthetics – both large and small.

Gail Brett Levine (NAJA)
Tracking Gemstones at Auction

The prices achieved at auctions for certificated rubies, emeralds and sapphires are not sufficient for valuations of other such gems without understanding the descriptive value factors, limitations of lab reports and country of origin. Subtleties such as transparency and clarity are major considerations which can result in auction prices that are considerable higher or lower than expected.

Menahem Sevdermish & Guy Borenstein (GemE Wizard)
Big Data Analysis and Insights in the Online Gem and Jewellery Trade

Big data analytics is the process of collecting, organizing and analyzing large data volumes to reveal hidden patterns and unfamiliar correlations, identify market trends, and extract other useful information which otherwise might be unnoticed – even to the data manager. The research and development team of Gemewizard® devised and digitized a fully automatic big gem data analysis system for large-scale gem and jewelry marketplaces, based on color and contextual search engine and image analysis the system generates unique market analytics and a fraud detection and prevention service. Some of these insights, considered fruitful and an eye opener for any marketplace or e-tailer, will be shared with conference participants.

Bear Williams (Stone Group Lab)
Insights into Gemmological Observations and Techniques

Lab gemmologists have a suite of instruments and devices at their disposal to analyse gemstones. The instruments vary from the simple to the advanced and they each have their strengths and limitations. Often the results can be surprising leading to further examination. With years of experience in a lab, Bear will discuss the challenges he has faced and the unexpected results with some gemstones.

Branko Deljanin (CGL-GRS Swiss Canadian Gemlab)
Gem Lab Notes from Canada

Accurate identification is first step in determining the commercial value of a gemstone. By using standard gem testing instruments and techniques, trained gemologists can recognize most common gems. Lab gemologists have a chance to test and compare properties of hundreds of gems and diamonds every week and to gain special knowledge and develop new techniques to allow positive identification. In cases of inclusion-free transparent or opaque gems or crystals/rocks additional advanced tests are required. Some of the rocks, minerals and gems examined at CGL-GRS lab include actinolte, amber, black gems, jade, rubies, sapphires, imitation “rough diamonds”, synthetic gems and others.

Martin P. Steinbach (MPS)
Asterism of Gems

One of the most intriguing phenomena in gems are the starry rays of asterism. Over 60 different gems can exhibit asterism with stars and trapiche varieties. The presentation will cover the history of asterism, the treatments and imitations of star stones, synthetic stars, double stars, networks of stars and 12—24 rayed star rubies, star sapphires, star qaurtzes, star spinels and others. Of special note will be the famous ‘Rosser Reeves’ star ruby and famous star sapphires like the ‘Star of India’.

Ans Anthonis (HRD Antwerp)
Red carpet for blue fluorescent diamonds? The relation between blue fluorescence and colour grading

To understand the effect of blue fluorescence on colour appearance, a selection of 160 round brilliant cut diamonds from a batch of more than 400 stones was investigated in detail with two different viewing geometries and under four different simulated lighting conditions: direct daylight, daylight through a window, grading light (D66 lamp) and generic store-ceiling light. For each colour, both experienced graders and non-diamond related professionals examined the possible effect of fluorescence on colour appearance. The investigation of the relation between fluorescence and colour, fits into a larger study that also analyses the origin of fluorescence and the possible effect of fluorescence on clarity and on the lustre of diamonds.

Ya’akov Almor
Present and Future of Synthetic Diamond Jewellery Industry – The Ethical Challenges

With the introduction of gem quality synthetic diamond to the jewellery markets, discussions have not only revolved around detection and identification, but also the ethical challenges such as disclosure, nomenclature, and the legitimacy of these products. Synthetic diamonds have proven to be a blessing in disguise, as the industry at large has been forced to invest in the generic promotion of natural diamonds, and consequently, to rethink how diamonds need to be marketed to the consumer. The possible scenarios for the future of jewellery featuring synthetic diamonds, and other synthetic gemstones will be explored together with the reputational and ethical challenges for jewellers and gemmologists.