Coloured Stone Commission report discusses challenge
of undeclared and undetected treated stones in market

AUGUST 23, 2023

With fewer than six weeks to go to the opening of the 2023 CIBJO Congress in Jaipur, India, on October 3, 2023, the fifth of the pre-congress Special Reports has been released. Prepared by the CIBJO Coloured Stone Commission, headed by Charles Abouchar, the report warns that the current high demand for coloured gemstones in the jewellery market could be threatened by heat-treated and irradiated stones, often corundum, making their way into the distribution chain.

“These frequently involve new treatments, some of which are actually old treatments that today are used in large numbers and, unfortunately, are not always detectable,” Mr. Abouchar writes. “In some cases they are not even tested for by gemstone laboratories.”

The treatments are not being carried out in backstreet facilities, the Coloured Stone Commission President states. “Today such activities are the domain of larger players, who have installed state of the art treatment facilities, and hired PhD graduates from various scientific disciplines to carry out the research needed,” he notes.

But, Mr. Abouchar continues, “Unfortunately, these new players do not always inform the gemmological and/or scientific worlds of their progress. It then falls upon those of us who are active in market to try to be on the lookout for goods that may have been subject to new treatments, or improved older ones.”

Identifying low temperature heating in rubies and other has been well researched, and many gem labs are now able to detect and report on such treatments, the Coloured Stone Commission President writes. But there are laboratories that do not have the required instrumentation and, even when there are testing protocols, methods vary between them, he says.

Irradiated corundum offers up different challenges, one of which is that the treatment is not always stable, with the stones eventually returning to their original colour. “The major trading issue with this treatment is that laboratories have not found a method of detecting that it has occurred, apart from, that is, by applying colour stability testing, which in itself does not confirm that a corundum has been irradiated, only whether the colour appearance is stable or not,” Mr. Abouchar writes.

The Coloured Stone Commission Special Report concludes with a tribute to Roland Naftule and Harry Levy, both of whom passed away earlier this year. Their legacy will continue through their massive contribution to the CIBJO Blue Books of industry standards and nomenclature, it notes. “[L]ike all great works of collective wisdom, the footprints of a select few are evident throughout, and the contributions they make will live on well on into the future, enriching the understanding, knowledge and sense of integrity of new members of our profession.”

To download a full copy of the CIBJO Coloured Stone Commission’s Special Report, PLEASE CLICK HERE.

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