GIA to Increase HPHT Treatment in Larger Stones
Type IIa diamonds...The Gemological Institute of America (GIA)’s New York lab has recently examined a number of HPHT-treated type IIa diamonds, many of which weighed 5-carat or more. It's revealed in GIA's December 7 G&G eBrief.
GIA gave an example of grading an 18.12-carat diamond that contained a graphite inclusion surrounded by a tension fracture.
While HPHT annealing runs a higher risk of damaging the stone, it was unusual to see it applied to bigger diamonds.
GIA stated the reasons behind a surge in submissions of treated diamonds remained unclear.
By: Denise Romano
Comments