GIA Institutes New Grading Policy for HPHT and Irradiated Diamonds


October 3, 2001

GIA Institutes New Grading Policy for HPHT and Irradiated Diamonds

The Gemological Institute of America's Gem Trade Labs have instituted a new grading policy for high pressure/high temperature-treated diamonds and artificially irradiated diamonds. When the GTL identify such gems, the diamonds will be laser-inscribed and the lab's findings detailed on the report.

When HPHT processes or irradiation in diamonds are detected by the Gem Trade Labs, that finding will be displayed prominently on the grading report. In the color section of the report, under origin, the disclosure will state that the diamond was either "HPHT Annealed" or "Artificially Irradiated." An asterisk next to this color section denotes further disclosure in the comments section.

GIA says that before the grading report is printed, the diamonds will be laser inscribed with "HPHT Processed" or "Irradiated" and any registered name that corresponds to the diamonds will also be inscribed. GIA's unique report number corresponding to the grading report will also be laser inscribed.

GIA's new grading policy was formulated as the industry sees increasing numbers of diamonds and diamond types that are subject to some form of color changes through HPHT annealing or irradiation. While experiments with HPHT have apparently gone on for some time, the diamond market only became aware of the dramatic changes it could have on diamonds two years ago when Pegasus Overseas Ltd., a subsidiary of Lazare Kaplan International, announced its new HPHT process. It was later revealed that General Electric Co. was supplying the technology to process certain Type IIa diamonds to convert them from brownish colors to the much more marketable colorless range. These diamonds are now sold as Bellataire™ processed diamonds. GIA, the Gübelin Lab (Lucerne, Switzerland), the SSEF Lab (Basel Switzerland), and others then embarked on projects to identify the characteristics of diamonds that had been processed by HPHT treatment.

"GIA has devoted a great deal of its research efforts to developing practical criteria for identifying HPHT annealing," says Tom Moses, GIA Gem Trade Labs vice president. "GIA has examined more than 3,500 GE-processed diamonds to date and has benefited from research performed by other esteemed organizations. As a result, GIA researchers have been able to isolate several gemological and spectral features that are effective in identifying HPHT processed diamonds."

"Because both HPHT annealing and artificial irradiation produce results that are stable in normal conditions of wear and care, we feel it is appropriate to issue GIA Grading Reports on diamonds that have undergone the process," adds Thomas C. Yonelunas, GIA Gem Trade Labs CEO. "The policy is in the best interests of the trade and the consumer as it both addresses the critical need for the disclosure of such processes, and provides a comprehensive analysis of the diamond's quality."

- by Robert Weldon, G.G.

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