Following the discovery of a diamond simulant Moissanite with a fraudulent GIA inscription, at GIA’s Johannesburg Laboratory, South Africa, as reported in the 2020 Falls Edition of GIA’s Quarterly Journal, Gems & Gemology, released in mid-January, the Gemological Institute of America has reported more detections of “Impostor” diamonds with fake inscriptions. These diamonds were either lab-grown or treated naturals, but bore fake inscriptions on their girdles relating to natural or untreated stones, previously graded by GIA.
The impostor diamonds recently detected were very close in weight and other grading parameters to the originals previously graded by GIA and the fake inscriptions also had the same GIA numbers.
One glaring example of an impostor diamond was a lab-grown, Type IIa, D-Color, VVS2-clarity diamond with a “Very Good” cut grade weighing 1.51212 carats, which was presented with a fraudulent report, claiming the stone to be a 1.50362-carat, VVS2-clarity, E-Color, Type IIa Natural Diamond with an “Excellent” cut grade. The fraudulent report is actually a report previously given by GIA for a natural diamond possessing the same grading parameters stated therein. Comparison of the two reports show that there is only a slight difference between the weights, color-grades and cut-grades.
GIA has not revealed to which of their labs the stones were submitted for grading or by whom. However, in keeping with their policy of discouraging such fraudulent practices, GIA continues to obscure fraudulent inscriptions, issuing new reports with accurate details, engraving correct report numbers on the girdle and where relevant the phrase “LABORATORY-GROWN” and is considering informing the client who submitted the stone, as well as the law enforcement agency and releasing details to the public.