(IDEX Online) - GIA has reported new instances of gems being submitted for grading with fraudulent inscriptions.
The diamonds were either lab-grown or treated naturals but bore inscriptions on their girdles relating to natural or untreated stones.
Last month its Johannesburg lab identified three cases of synthetic moissanite being passed off as diamonds, all bearing fake inscriptions.
In the more recent frauds, the "impostor" stones were close in weight and grading parameters to the originals and were inscribed with their GIA numbers.
In one example, the report that accompanied a diamond submitted for an update was for a 1.50362 carat, VVS2, E, type I natural diamond with an excellent cut grade.
The newly-submitted stone with a counterfeit inscription was a man-made diamond, 1.51212 carat, VVS2, D, type IIa with a very good cut grade.
GIA has not said where the stones were submitted for grading, or by whom.
Pic shows a diamond newly inscribed as "Laboratory-grown" by GIA...