For natural diamonds, GIA and IGI both grade the 4Cs. For lab-grown diamonds they now differ: in 2025 GIA said it would stop using its color and clarity terms for lab-grown stones and describe them as "premium" or "standard," while IGI said it will keep grading lab-grown diamonds with the 4Cs. AGS, the third name you may see on older reports, closed its laboratory at the end of 2022 and merged its operations with GIA.
GIA vs. IGI at a glance
| GIA | IGI | |
|---|---|---|
| Natural diamonds | Full grading on its D-to-Z color scale | 4Cs grading |
| Lab-grown diamonds | "Premium" or "standard" descriptions instead of color and clarity grades (announced June 2, 2025) | Continues 4Cs grading (stated July 2025) |
Why did GIA change its lab-grown reports?
GIA's June 2, 2025 announcement said it would "no longer use the color and clarity nomenclature that GIA developed for natural diamonds" for lab-grown stones, describing them instead as "premium" or "standard." Its reasoning, from Tom Moses, GIA's 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 color and clarity." (GIA press release)
Does IGI still grade lab-grown diamonds with the 4Cs?
Yes, as of its July 2025 statement. IDEX Online reported that "IGI says it has no plans to stop grading lab growns for color and clarity," and that it would keep the 4Cs "to prevent industry and consumer confusion." (IDEX Online, July 15, 2025)
What happened to AGS?
The American Gem Society announced in 2022 that "it will close AGS Laboratories at the end of the year and merge its operations with the Gemological Institute of America," and that "AGS Labs will continue to provide services until the end of 2022" (National Jeweler). Older AGS reports still describe the stones they graded; new grading goes to other labs.
Which report should you want for a lab-grown diamond?
GIA describes its lab-grown service as an assessment "ensuring disclosure through laser inscription." Beyond that, choose based on what you want to compare: if you want to compare lab-grown stones grade by grade, an IGI report gives you familiar color and clarity grades; a GIA report tells you whether the stone meets GIA's "premium" or "standard" description. Whatever the report, two rules from the FTC's Jewelry Guides protect you:
- If a seller quotes a grade, "the identity of the grading system used should be disclosed" (16 CFR 23.1).
- A lab-grown diamond must be named lab-grown, with equal prominence, every time (16 CFR 23.25).
How do you check that a report matches the stone?
Two checks, both quick. First, look the report number up on the lab's own website (GIA's lookup is called Report Check) and confirm the shape, measurements and carat weight match the paperwork you were given. Second, compare the stone itself: for a GIA lab-grown report, "The laboratory-grown diamond's girdle is laser inscribed with "Laboratory-Grown" and the GIA quality assessment number." (GIA). Ask the jeweler to show you that inscription under magnification and check it against the report.
How this works at our showroom
Every diamond in our online catalog is lab-grown and named that way. If a lab report matters to you, ask us before you buy which lab, if any, graded the stone in a particular piece and for the report number, so you know exactly what comes with it. For more, read how to tell if a diamond is lab-grown, are lab-grown diamonds real diamonds? and our guide to the 4Cs, or browse all lab-grown jewelry.
