GIA Laboratory-Grown Diamond Report

The GIA Laboratory-Grown Diamond Report is GIA's grading credential for synthetic diamonds. GIA began grading lab-grown stones in 2007 with a separate descriptive scale (Colorless / Near-Colorless instead of D-Z) and switched to the full D-Z and FL-I3 numeric scales in 2020. The 2020 alignment removed the previous "GIA does not call lab-grown by letter grade" pricing distortion and put lab-grown grading at par with natural.

The report includes color grade (D-Z), clarity grade (FL through I3), cut grade where applicable (Excellent through Poor on rounds), polish, symmetry, fluorescence, and measurements. The growth method (CVD or HPHT) is disclosed under "Origin." Post-growth treatments are disclosed under "Treatment" — most commonly "HPHT" for CVD stones that received post-growth color treatment. The report carries a laser inscription on the girdle reading "Lab Grown" followed by the GIA report number; the inscription is verifiable against the GIA Report Check online database.

GIA lab-grown reports trade at a 5% to 10% retail premium over IGI lab-grown reports at the same paper grade. The premium reflects GIA's brand position rather than measurably tighter grading — though GIA grading is widely understood to run slightly stricter than IGI at the borderlines between adjacent grades. In wholesale and trade-desk pricing the GIA premium narrows to 2% to 5%.

GIA's October 2025 policy change is the headline 2026 fact for lab-grown grading. Beginning October 2025, GIA stopped issuing granular color and clarity grades on lab-grown reports and switched to a descriptive scale ("Premium" / "Standard") for cut grade only. The change applied to new reports issued after the policy date; legacy GIA lab-grown reports with letter grades continue to circulate in the secondary market. The trade impact has been to push new lab-grown grading volume back toward IGI for buyers who want letter-grade paper, and to elevate the AGS Ideal Report supplement (still available on GIA naturals and on qualifying GIA lab-grown rounds) as the differentiator for the lab-grown super-ideal tier.

The 2025 GIA change is the load-bearing 2026 lab-grown buying fact. A buyer comparing IGI letter-grade paper against GIA descriptive paper on lab-grown rounds should weigh the GIA brand premium against the loss of granular color and clarity grading; for most buyers the IGI letter grade is the more useful credential despite the smaller brand premium.

GIA grades natural and lab-grown to nominally equivalent standards but the two reports use distinct visual designs to prevent confusion. Natural reports are on cream paper with the GIA logo in the upper-left; lab-grown reports are on white paper with prominent "Laboratory-Grown" headers.