GIA to introduce new descriptive grading system for lab-grown diamonds, phasing out traditional 4Cs

Beginning later this year, GIA (the Gemological Institute of America) will start using descriptive terms to characterise the quality of laboratory-grown diamonds (LGDs) and will no longer use the colour and clarity nomenclature that GIA developed for natural diamonds. The Indian diamond trade said that for consumers, it brings greater transparency and ensures that purchasing decisions are based on a clear understanding of a diamond’s origin and characteristics.

The Institute will continue to accept laboratory-grown diamonds for evaluation and identification.

The revised GIA description system for laboratory-grown diamonds will confirm that the submitted item is a laboratory-grown diamond and whether it falls into one of two categories, ‘premium’ or ‘standard.’ The categories will be defined by a combination of metrics related to colour, clarity and finish. If the man-made diamond fails to achieve the minimum standard for quality, it will not receive a designation from GIA. Until the revised descriptive system for laboratory-grown diamonds is finalised, the current GIA services for laboratory-grown diamonds will continue to be available.

“Similar to other man-made gem materials, we anticipate the continued acceptance and popularity of laboratory-grown diamonds,” said Tom Moses, GIA executive vice president and chief laboratory and research officer. “More than 95% of laboratory-grown diamonds entering the market fall into a very narrow range of colour and clarity. Because of that, it is no longer relevant for GIA to describe man-made diamonds using the nomenclature created for the continuum of colour and clarity of natural diamonds.”

Commenting on GIA's decision, Kirit Bhansali, chairman of Gem & Jewellery Export Promotion Council, said, “GIA’s decision to use descriptive terms instead of the famous 4Cs grading for laboratory-grown diamonds marks an important evolution in diamond classification. This change will help eliminate confusion by clearly distinguishing how lab-grown diamonds are assessed, separate from the standards developed for natural diamonds. For consumers, it brings greater transparency and ensures that purchasing decisions are based on a clear understanding of a diamond’s origin and characteristics. For India, as a leading hub for both natural and lab-grown diamonds, this change brings much-needed clarity and balance to the marketplace, allowing both categories to grow with greater transparency, integrity, and consumer confidence.”

GIA developed the universally accepted colour and clarity scales for natural diamonds in the 1940s to communicate their characteristics and reduce consumer confusion. This change to how GIA describes the quality of laboratory-grown diamonds will help consumers understand the important differences in the two products’ origin, ensuring their confidence and enabling them to make informed and educated purchase decisions.

Pricing and submission guidelines for the revised GIA service for laboratory-grown diamonds are in development and will be announced late in the third quarter. Existing GIA reports for laboratory-grown diamonds remain valid, a release issued by the institute said.