GIA ends D–Z clarity grading for lab-grown diamonds, adopts Premium/Standard system

The Gemological Institute of America has retooled how it grades lab‑grown diamonds, retiring the traditional D–Z color scale and FL–I3 clarity scale for created stones and issuing a simplified Quality Assessment that places each lab‑grown diamond into either "Premium" or "Standard." Tom Moses, GIA’s executive vice president and chief research and laboratory officer, framed the change by noting that "More than 95% of laboratory‑grown diamonds entering the market fall into a very narrow range of color and clarity," and adding, "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."

Implementation and timing have been reported in slightly different terms. Rob Bates wrote for JCK on June 3, 2025 that GIA would stop using the D–Z and FL–I3 scales and move to the two classifications "later this year," and that GIA planned to announce pricing for the new reports in the third quarter. Kinnstudio and Naturaldiamonds state that the new framework was introduced on October 1, 2025, with Naturaldiamonds describing the change as taking effect "beginning today" in its October 1, 2025 update.

Under the new mechanics described by multiple outlets, lab‑grown stones will carry a permanent laser inscription that reads "Laboratory‑Grown" alongside a unique GIA Quality Assessment or assessment number; Kinnstudio and Shop Kenanddanadesign both emphasize the continued inscription practice. The paperwork itself is being called a Quality Assessment by some sources, and those reports will assign the two‑word labels rather than letter grades; JCK noted that GIA said the Premium and Standard categories "will be defined by (as yet unspecified) metrics related to color, clarity, and finish."

Outlets differ on how GIA will handle stones that do not meet minimum thresholds. Burdeen’s Jewelry uses the word "Uncategorized" for such stones, JCK reported they "won't receive any designation," Naturaldiamonds wrote they may receive "no grade at all," and Shop Kenanddanadesign said diamonds below Standard "won't receive any report." Shop Kenanddanadesign also cataloged the visible consequences: no more exact color grades like G, F, or E and no more precise clarity grades like VS1 or SI2 for lab‑grown stones, summarizing the shift under a practical headline that mirrors Kinnstudio's: "No More Full Color or Clarity Grades."

Industry response has been mixed and pointed. Grant Mobley of the Natural Diamond Council called the decision "a definitive moment in the ongoing separation of natural diamonds from lab‑grown diamonds." Amish Shah, CEO of ALTR, posted on LinkedIn and was quoted by JCK saying, "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." A retailer voice at Shop Kenanddanadesign cautioned, "If this rollout creates confusion or undermines trust, GIA may shift back to more detailed grading," and urged jewelers to continue showing customers the granular details behind any two‑word label.

Natural diamonds remain unaffected: Kinnstudio and JCK both note that natural stones will continue to receive the full 4 Cs, Color, Clarity, Cut, Carat, and that existing GIA documents remain valid. GIA’s announced change, reported in mid‑2025 and in some accounts formalized on October 1, 2025, redraws how certification will present lab‑grown stones and forces retailers, insurers, and appraisers to adapt to a world where many created diamonds are summarized by a single Quality Assessment label rather than a string of letter grades.