In each of the last five issues of Gems & Gemology, we have published articles on the high pressure/high temperature (HPHT) annealing of diamonds to modify their color. This is arguably one of the most serious challenges the diamond industry has ever faced. Most of these articles have dealt with the decolorization of diamonds as represented by the GE POL process. The paper by Christopher Smith and his colleagues in the present issue is the most recent contribution. It provides some important new data on the characteristics of GE POL diamonds before and after processing.

What, though, does all this mean for the jeweler and gemologist? In particular, what do all these developments mean for a laboratory that is entrusted with the responsibility of identifying these and other treated or synthetic diamonds?

The role of the gemological laboratory has changed in many ways over the past decade. Not only have the techniques and instrumentation for gem identification become more advanced, the methods and steps in diamond grading have become much more extensive and sophisticated. The new developments in treatments to diamonds and the further advancement of synthetic diamond growth methods have made it necessary for a gemological laboratory to become well equipped and to continually modify the screening methods used to detect such diamonds.

While I cannot speak for all laboratories, there have always been processes incorporated into the servicing procedures of the GIA Gem Trade Laboratory to meet the challenges of synthetics, coatings, fillers, laser drilling, and irradiation. More than a dozen additional detection techniques and instruments have been added to this process in the last five years alone.

Overall, the GIA system has been designed to ensure accuracy, efficiency, and client anonymity throughout the grading process. There are meticulous electronic routing techniques that guide a diamond through the laboratory, which include numerous steps that capture well over 400 separate and distinct pieces of gemological and scientific information.

After careful weighing and measuring, each diamond is processed through a series of instruments designed to differentiate natural from treated and synthetic diamonds, as well as to detect and distinguish diamond types. These include, but are not limited to, the De Beers DiamondSure, short-wave ultraviolet fluorescence transparency devices, and proprietary spectroscopic instruments designed to measure the presence and level of trace elements, such as nitrogen, in each diamond.

All diamonds that are determined to be type II are then further screened by GIA’s most experienced gemologists and research scientists. Some of the techniques and instruments employed include UV-Vis-NIR spectroscopy, high-resolution infrared spectroscopy, and (low temperature) Raman analysis to determine key photoluminescence features. Results from these analyses are then compared with our extensive database on known HPHT-annealed diamonds and untreated type IIa’s.

Based on our careful examination of well over 2,000 GE POL diamonds to date, we believe that the vast majority of diamonds that have been de-colorized by HPHT annealing can be identified through their properties, the laboratory’s grading and research experience, and the data archived in the laboratory’s Horizon operations and management information system.

The proliferation of diamond treatments also raises questions about the fair and accurate representation of these products to tradespeople and consumers alike. There are legitimate markets for enhanced diamonds and an important need for consumers to know exactly what they are purchasing. As a result, we are currently reviewing our reporting policy for some enhanced diamonds and the scope of services we offer.

Yes, there are challenges to the way laboratories must now operate. We must gather more information, using more sophisticated instrumentation, in a process that often requires more time and a tremendous investment in equipment and personnel. Because many of these new treatments cannot be detected with standard gemological equipment, we are all serving a much broader constituency. Nevertheless, we believe that with solid research, with continued cooperation from the trade, and with flexibility and ingenuity, we and other well-equipped gemological laboratories will be able to continue to meet the needs of both the trade and the public.

William E. Boyajian, President
Gemological Institute of America