The International Gemological Institute recently graded a 6.01-carat, pear-shaped lab-grown diamond (left) that was inscribed with the GIA report number seen at right, which is for a natural diamond.
Tel Aviv, Israel—The International Gemological Institute’s laboratory in Tel Aviv recently detected a 6-carat lab-grown diamond that someone apparently was hoping to pass off as a natural stone.
The 6.01-carat, pear-shaped synthetic diamond was fraudulently inscribed with the Gemological Institute of America report number for a G-color natural diamond of the same size and shape, but with a few key differences, IGI said in a news release issued Tuesday.
First, the lab said, photoluminescence (PL) spectroscopy, which is now widely used by grading labs to separate natural diamonds from lab-grown stones and to identify diamond treatments, shows a wavelength peak of 737 nanometers in the diamond (see chart below).
This is an indicator that the diamond was grown in a factory using the chemical vapor deposition process.
The photoluminescence spectra for the 6.01-carat lab-grown diamond recently examined by the International Gemological Institute
Second, when examined under a microscope, IGI graders saw a carbon inclusion where the feather was indicated on the clarity plotting diagram in the GIA report.
They also noticed a cloud inclusion, resulting in IGI giving the lab-grown diamond a lower clarity grade than VVS1, the clarity grade of the natural diamond.
Lastly, there was a discrepancy between the depth of the diamond IGI examined and the depth noted on the GIA report.
“Everyone in our industry must be vigilant,” said IGI CEO Tehmasp Printer, who took over as head of the lab in October after Roland Lorie retired.
“As attempted fraud increases, the need for ongoing verification is a necessary step to protect consumers from purchasing misrepresented gems and jewelry.”
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The news from IGI comes on the heels of a story from Rapaport about Italian grading lab Gem-Tech finding three lab-grown diamonds inscribed with GIA report numbers for natural diamonds.
According to the report, those diamonds were accompanied by physical grading reports stating they were natural diamonds.
However, like the 6.01-carat lab-grown diamond examined by IGI, the stones Gem-Tech examined displayed characteristics normally only seen in diamonds grown using the CVD process.
Also like IGI graders, the Gem-Tech graders noticed the three submitted stones were slightly different than the diamonds described in the grading reports.
GIA issued a news release about fraudulent inscriptions back in May 2021 following a string of incidents earlier that year, including the submission of three moissanites engraved with report numbers for natural diamonds and the submission of a mix of lab-grown diamonds and treated natural diamonds engraved with fraudulent report numbers.
In that release, Tom Moses, GIA executive vice president and chief laboratory and research officer, said, “This unfortunate situation demonstrates why it is important, especially in any transaction where the buyer does not have a trusted relationship with the seller, to have the diamond grading report updated before completing a purchase.”
GIA said it has seen “several” lab-grown diamonds with counterfeit inscriptions referencing GIA diamond grading reports for natural diamonds.
These lab-grown diamonds have measurements and weights that are almost identical to the GIA reports but the differences are “significant enough to raise concerns.”
