GIA Spots ‘Precise’ Attempt at Lab-Grown Fraud

RAPAPORT… The Gemological Institute of America (GIA) has uncovered a synthetic diamond with a forged inscription that fraudsters used to “precisely match” a similar natural stone.

A round brilliant, chemical vapor deposition (CVD) stone weighing 3.078 carats was submitted to the GIA’s Antwerp lab for its update service, the institute reported last week in the summer 2021 issue of Gems & Gemology. The inscription matched that of a natural diamond originally sent for grading in 2018.

“Comparison showed an attempt to precisely match the lab-grown diamond to the information contained in the original report,” the lab noted. “Both were round brilliants with excellent cut properties and very close in carat weight and measurements.”

However, further analysis showed the natural diamond was a G-color, internally flawless stone, while the CVD diamond was 3.075 carats, with H color and VVS2 clarity. Advanced spectroscopic techniques also found the original diamond graded in 2018 was a type Ia and had a high concentration of nitrogen. The lab-grown diamond was a type IIa with a weaker level of nitrogen, the GIA explained.

In addition, the new submission displayed a typical CVD growth structure, with a green-blue layered pattern and banded layers indicating a start-stop growth. A High Pressure-High Temperature (HPHT) treatment had been applied to the synthetic stone post-growth. The GIA replaced the counterfeit inscription with one marked “laboratory grown” and issued a new report.

The GIA has seen a number of counterfeit inscriptions in recent months, it added.

Image: The 3.08-carat lab-grown diamond. (Gemological Institute of America)