GIA Identifies CVD Synthetic Diamonds in Hong Kong Lab
July 12, 12
(IDEX Online News) –Ten diamonds submitted to GIA’s Hong Kong lab were identified as CVD-grown synthetics, and connected them indirectly to Gemesis. GIA said in a Lab Update in the latest edition of GIA’s G&G eBrief that the stones appeared comparable to their natural counterparts. 
The round brilliant diamonds ranged from 0.30 to 0.35 ct, with F–H color grades. Their clarity grades ranged from VVS1 to VVS2, and one sample received a VS1 grade.
GIA said the gemological and spectroscopic features of the diamonds were similar to those observed in Gemesis CVD synthetic diamonds. This, said the lab, suggests, “Post-growth annealing at high temperature was applied to improve their color and possibly their transparency.”
Labs are increasingly on the lookout for synthetic diamonds being passed off as natural without their origins being disclosed.