Recently, the Gemological Institute of America (GIA) announced an important change in its approach to certifying synthetic diamonds. By the end of 2025, the institute will introduce a new quality scale that uses general descriptions instead of the traditional 4Cs grades used for natural diamonds. Specifically, each lab-grown diamond examined by GIA will be identified as such and classified simply as “Premium” or “Standard”, if it meets the defined standards, or it will not receive any category if it is of lower quality. This decision reflects the technological and market evolution in the synthetic diamond sector and aims to more clearly outline the differences compared to natural diamonds.
GIA’s move comes in a context of rapid growth in lab-grown diamonds and technical advances in their production. At the same time, continuous improvements in HPHT and CVD processes have made these products homogeneous in terms of quality. GIA has observed a drastic compression of color and clarity variability in current lab-grown diamonds: since 2022, over 95% of lab-grown diamonds analyzed by GIA are colorless (grade D–F) and 98% have a clarity of VS1 or higher. In practice, almost all lab-grown diamonds placed on the market fall within these classifications, as they are artificially produced and replicable in large quantities.
As a result, using the fine grading of the 4Cs—designed for the wide spectrum of natural diamonds—has become less meaningful for synthetics. “More than 95% of lab-grown diamonds fall within a very narrow range of color and clarity. For this reason, it is no longer relevant to describe them with the nomenclature designed for the continuum of natural diamonds,” explains Tom Moses, executive vice president of GIA. The update therefore aims to “help consumers understand the important differences in origin between the two products,” strengthening trust and transparency in transactions.
With the new descriptive system, GIA will first confirm the synthetic origin of the stone and then place it into one of the two planned quality categories. The “Premium” category will indicate a lab-grown diamond of high overall quality, while “Standard” will refer to good/commercial quality; both will be determined by a combination of parameters such as color, clarity, and finish (cut appearance, symmetry, polish). If the diamond does not meet the minimum requirements defined for the Standard category, the report will not assign any quality designation, limiting itself to identifying it as a lab-grown diamond. This revision therefore replaces detailed color and clarity grades with macro-categorical evaluations. GIA will continue to accept lab-grown diamonds for analysis and identification during the transition phase, until the new system officially comes into effect by the end of the year. Existing GIA certificates for lab-grown diamonds will remain valid even after the change.
GIA has announced that operational details, including final technical criteria and pricing for the new service, will be released by the third quarter of 2025.
This change marks a significant evolution compared to GIA’s previous policies on lab-grown diamonds.
PUBBLICAZIONE
16/06/2025
Supplied by Assogemme
