GIA Lab Alert Identifies Surge in HPHT-Treated Submissions

Vast Majority of Diamonds Lacked Full Disclosure:


The Gemological Institute of America (GIA) Laboratory recently reported that a significant number of large high pressure/high temperature (HPHT) treated-color diamonds were submitted for grading. Submissions have ranged from 3-carat to nearly 20-carat stones and the vast majority of these diamonds were submitted without full disclosure. The color grades ranged from “D” to “J”, but most were “G” or better combined with high clarities.

As already noted in GIA's December issue of Gems & Gemology’s G&G eBrief, some of the diamonds had flat graphite inclusions with tension “halos” surrounding them. This type of inclusion suggests that the diamond has been processed by HPHT annealing.

“The range of diamonds being subjected to the treatment has also expanded,” said Tom Moses, senior vice president of the GIA Laboratory and Research. “We are confident that we can identify virtually all these treated diamonds as a result of our extensive research in this area, which is one of the most important initiatives at GIA. However, we do not know if this recent surge in treated stones represents a new source or an attempt by some clients to ‘test the systems’ at GIA.”

According to Moses, GIA is contacting the clients both to learn the source of the treated diamonds and to remind them that the failure to disclose treatment at all stages of the pipeline is unacceptable. In addition, GIA is reviewing each transaction to determine whether it’s appropriate to turn over relevant information to the trade organizations and law enforcement bodies.

“GIA’s mission is to protect the public trust in gems and jewelry,” added Moses. “We take this role very seriously. GIA will not tolerate the intentional failure of its clients to appropriately disclose gemstone treatments.”

By Jeff Miller