GIA Changes Policy on HTHP Diamonds

The Gemological Institute of America’s Gem Trade Laboratory has announced a new grading policy for diamonds that have been processed by high pressure and high temperature (HPHT) or have been irradiated artificially.

When one of these processes is detected, the report will include an “Origin” field in the Color section that will state either “HPHT Annealed” or “Artificially Irradiated,” and an asterisk next to the actual color grade that references disclosure in the “Comments” section.

GIA also will require that the diamonds be laser inscribed with the words “HPHT PROCESSED,” “IRRADIATED,” or a specific “brand” name before they are graded.

GIA does not grade fracture-filled diamonds, but GTL officials say that they will grade irradiated and HPHT diamonds that are stable in normal conditions of wear and care.

Lab officials told JCK that they have seen HPHT diamonds that do not come from known manufacturer Bellataire and were not disclosed to the lab. (See “The Heat—and Pressure—is On,” JCK, November 2001, p. 102.)

GIA is making one concession to Bellataire: Its release—and reports—consistently uses the word “processed,” rather than “treated,” the word favored by most gemologists.