Italian gemological lab Gem-Tech has warned the trade that a number of lab-grown diamonds circulating in the country are being sold as natural.

Three stones were submitted to the lab accompanied by certificates from the Gemological Institute of America (GIA) stating they were natural, Gem-Tech said last week. Gem-Tech weighed the stones and found them to be almost identical to those recorded on the GIA certificates. The stones also have laser inscriptions with a visible GIA logo that matches those the lab had seen before from other GIA-graded stones, Gem-Tech explained.

However, further investigations indicated the stones had been fraudulently paired with the grading reports, while the inscriptions appeared to be forgeries.

When the Italian lab exposed the diamonds to ultraviolet light to detect fluorescence, it discovered that the stones were inert, whereas the reports described the level of fluorescence as “faint.” The diamonds were then checked using spectrophotometric analysis and displayed a distinct greenish coloration and other characteristics commonly found in synthetics created using chemical vapor deposition (CVD).

Once the lab checked the report numbers against the GIA website, it realized they were issued for other, natural, stones that were just slightly different than those submitted to Gem-Tech.

“Gem-Tech has seen this happen before,” the lab said. “It would not be the first time that malicious individuals obtained reprints of authentic reports and paired them with stones other than those described.”

Although there were only three stones submitted, Gem-Tech believes there might be more, it is told Rapaport News.

“The client who submitted them for identification reported that these stones were not the only ones being offered,” the lab added. “Other dealers have mentioned that these three synthetic diamonds, identified by their report data, have been presented in other parts of the country.”

If consumers are purchasing a diamond from a seller they do not have a relationship with, they should have the grading report updated by the GIA before completing the sale, the GIA said in a statement to Rapaport News.

“We have seen an increase in fraudulent inscriptions on stones submitted to GIA in several locations and depending on the circumstances of the submission of stones with counterfeit inscriptions, GIA considers all of the options outlined in GIA’s client agreement, including notifying the submitted client, law enforcement, and the public,” the GIA added.

Image: The girdle of one of the lab-grown diamonds, showing what appears to be a forged GIA laser inscription. (Gem-Tech)

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By ting