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GIA Spots Treatment Fraud with 6ct. Polished
May 30, 2018 10:35 AM
By Rapaport News
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RAPAPORT... The Gemological Institute of America (GIA) has uncovered a
treated diamond carrying a false inscription that fraudsters had apparently
created to make the stone appear untreated.
Swindlers appear to have carefully selected a grading report
for an untreated diamond with extremely similar characteristics to their
treated stone, and created a fake GIA laser imprint on the treated stone’s
girdle, according to a grader’s lab note.
The organization’s Hong Kong laboratory received the round
brilliant, 6.30-carat, F-color, internally flawless natural diamond for
verification of its grade, Billie Law, who works at the GIA in Hong Kong, wrote
in the spring 2018 issue of the institute’s journal, Gems & Gemology.
Scientists found the polished stone’s characteristics were
inconsistent with a report the GIA had issued a few months earlier for a
diamond with an identical code on its girdle. That number referred to a
fractionally smaller diamond — 6.30216 carats, in contrast with the
6.30402-carat stone in front of them — with F color but VVS1 clarity.
The other difference was that the stone the gemologists had
in their hands was clearly treated using High Pressure-High Temperature (HPHT),
a common method for improving a diamond’s color. The scientists checked this
using spectroscopic testing that easily revealed the stone’s true nature, Law
wrote.
“This case should raise awareness among the industry and the
public that, although rarely encountered in larger stones, this kind of fraud
does exist,” the grader continued. “Verification services at GIA confirm that
an item is exactly the same as the one described on a previous report and has
not been recut or treated — or, as in this case, replaced with a
similar-looking stone.”
Grading laboratories have discovered several such cases in
recent years, though usually involving smaller stones. In 2017, the GIA
identified a girdle inscription on a 1.76-carat synthetic diamond to be a
forgery created by fraudsters trying to pass it off as a natural stone. Last
month, China’s National Gemstone Testing Center said it had received a 3.10-carat
synthetic-diamond ring carrying a fake report and inscription that falsely
presented it as natural.
Images: Tony Leung and Billie Law
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Tags:
Billie Law, diamond grading, fraud, Gemological Institute of America, GIA, grading, Grading labs, Hong Kong, HPHT, HPHT treatment, Laboratories, Labs, Rapaport News, treated diamonds, treatment
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