GIA Changes Its Lab-Grown Grading (Again)

By Rob Bates | June 03, 2025

Later this year, GIA will stop grading lab-grown diamonds by the color and clarity scale it uses for natural diamonds and instead use two broad classifications: “premium” and “standard.”

Those categories will be defined by (as yet unspecified) metrics related to color, clarity, and finish, GIA said in a statement. If a created diamond does not achieve GIA’s minimum quality standards, it won’t receive any designation, the lab added.

“More than 95% of laboratory-grown diamonds entering the market fall into a very narrow range of color and clarity,” Tom Moses, GIA’s executive vice president and chief research and laboratory officer, said in the statement. “Because of that, it is no longer relevant for GIA to describe man-made diamonds using the nomenclature created for the continuum of color and clarity of natural diamonds.”

According to GIA, the change “will help consumers understand the important differences in the two products’ origin.”

GIA will announce a price for the new reports in the third quarter. The new policy doesn’t affect GIA’s existing lab-grown reports, which remain valid, it said.

This will be the third system GIA has used for grading lab-growns. In 2006, when GIA first began issuing reports for “synthetic” diamonds, it grouped them into general categories (including “near colorless” and “VVS”) instead of using standard diamond grades.

In 2020, GIA began grading lab-growns using full 4Cs nomenclature. (It had removed the word synthetic from reports in 2019.)

Throughout all the changes, GIA has never become the lab of choice for created diamonds. Its president and CEO, Susan Jacques, told JCK earlier this year that GIA grades fewer than 5% of lab-grown diamonds on the market.

“At [current lab-grown] prices, certification doesn’t really make sense any longer,” she said.

GIA’s new policy was hailed by the Natural Diamond Council (NDC), which was the first source to announce it.

“This move marks a definitive moment in the ongoing separation of natural diamonds from lab-grown diamonds,” wrote NDC’s Grant Mobley. “It confirms what many in the industry have long known: Lab-grown diamonds are not the same as natural diamonds and should not be treated as such.”

By contrast, Amish Shah, CEO of ALTR, a lab-grown company, wrote on LinkedIn: “The GIA’s decision to overhaul its grading system for lab-grown diamonds (LGDs) feels less like innovation and more like repositioning after failing to dominate market share…. this reeks of an industry scrambling to maintain differentiation as LGDs eat into even the premium segment.”

(Photo courtesy of GIA)