Grading labs under the microscope as science of treating diamonds advances

Martin Rapaport

The global business of diamond grading was under the microscope at last week’s Rapaport conference with labs urged to sign up to a global set of standards.

Rapaport is a campaigning group for the jewellery and diamond trade, and hosts a conference in the USA for diamond professionals every year.

The Gemological Institute of America (GIA), which is widely viewed as the highest authority on diamond grading, admitted at the Rapaport conference that it could not force all labs to sign up to a single set of diamond grading rules.

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This prompted Rapaport chief operating officer Saville Stern, who was moderating a discussion on grading standards to call for legal action against labs that do not comply with GIA standards.

“If we allow labs to follow their own standards, and call something a D when it is a K, we are going to bring the downfall of our industry,” Stern said.

Diamond grading is in the spotlight as new techniques to treat and improve diamonds are muddying the waters of certification.

However Rapaport chairman Martin Rapaport (pictured above) struck a more pragmatic tone. Ultimately, grading is not a precise science he admitted, and consumers should be made aware of this. “Diamond trading is subjective. There is a standard, and you can move a little bit to the right to the left. Legitimate diamond grading labs should be within one grade of what the GIA says,” he said.


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