GIA Warning over Fraudulent Inscriptions

(IDEX Online) - GIA has again warned of fraudulent inscriptions, after intercepting four impostor diamonds at its Dubai lab.

The stones were all submitted for updated services, and were all close matches in terms of weight, color, clarity, cut, polish and symmetry to genuine natural diamonds that had previously been graded by GIA.

But GIA staff were alerted by the inscriptions - which were in unusual places and used inconsistent font styles.

It turned out that two of the impostor diamonds were lab growns, and two were natural diamonds that had undergone HPHT treatment to improve or change their color.

The GIA Gems & Gemology Summer 2025 issue details small differences between the impostor stones and their genuine counterparts. All were exactly the same weight, although the dimensions varied slightly.

Three out of four had the same color, one was D, compared with E. Three out of four also had the same clarity, but one was VS1 rather than VVS1.

"Considering all evidence, we concluded that two of the four stones were laboratory-grown diamonds, and the other two were HPHT-processed natural diamonds," GIA said.

"All four diamonds were not the same natural diamonds as described in their accompanying GIA grading reports.

"In accordance with GIA procedures, the counterfeit inscriptions were crossed out and new report numbers were assigned."

It said the stones were newly inscribed as being lab grown or treated.

"Deceptive practices have occurred previously in the trade," it said. "These cases highlight the importance of verifying inscription authenticity because a fraudulent inscription could be overlooked by simple visual examination."

Pic courtesy GIA shows details of the two lab growns, one pictured in A&B, the other in C&D