IGI Discovers 6ct. Lab-Grown Diamond Posing as Natural

A 6.01-carat stone that the International Gemological Institute (IGI) recently received for grading turned out to be a synthetic diamond with a laser inscription for a natural one.

The pear-cut lab-grown diamond’s carat weight and physical description were a close match to the online data for a natural diamond graded by the Gemological Institute of America (GIA), whose inscription it bore, the IGI said Tuesday. However, after testing the stone, the lab concluded it was not a natural diamond and, therefore, that someone must have fraudulently paired the natural-diamond report with a synthetic stone.

The institute used photoluminescence spectroscopy to test the diamond, which revealed a doublet caused by silicon-vacancy (SiV) defects, indicating it was created using chemical vapor deposition (CVD). Further review of the stone using microscopy showed a carbon inclusion in place of the feather noted in the GIA report, as well as a cloud, which resulted in a lower clarity grade. IGI also found a slight mismatch in the depth of the stone, but observed those small discrepancies could easily go unnoticed outside of a laboratory, particularly after the stone had been set into a piece of jewelry.

“Everyone in our industry must be vigilant,” said IGI CEO Tehmasp Printer. “As attempted fraud increases, the need for ongoing verification is a necessary step to protect consumers from purchasing misrepresented gems and jewelry.”

The discovery of the fraudulent stone comes on the heels of a number of other industry alerts that lab-grown are being sold as natural, the IGI added.

Italian lab Gem-Tech recently identified three synthetic diamonds bearing GIA inscriptions that appeared to have been forged.