IGI and GIA both certify lab-grown diamonds. Both are legitimate. But their grading standards for lab-grown stones are not identical — and the difference affects what you pay and what you get.

What the Certificates Do

A grading report from IGI or GIA tells you the four Cs for a specific stone: cut, color, clarity, and carat weight. The report number is laser-inscribed on the stone's girdle so you can match the physical stone to the certificate. Both organizations allow you to verify a report online — IGI at igi.org, GIA at gia.edu. Always buy certified.

GIA for Lab-Grown Diamonds

GIA is the most widely recognized grading authority in the world. For lab-grown diamonds, GIA changed its reporting format in 2020 — GIA lab-grown reports use descriptive color and clarity ranges rather than specific grades. So instead of "E color, VVS1 clarity," a GIA lab-grown report might state "Colorless" and "VVS." This reduces the specificity that buyers need to evaluate stones accurately. Some recent GIA lab-grown reports do include specific grades — check the certificate format.

IGI for Lab-Grown Diamonds

IGI has been the primary certifier for the lab-grown diamond market and issues specific, precise grades: a specific color grade (D, E, F, G) and a specific clarity grade (VVS1, VVS2, VS1). This precision matters for comparison shopping. IGI has become the dominant certifier for lab-grown diamonds because its reporting format is appropriate for the product.

Which Certificate Should You Ask For?

For lab-grown diamonds: IGI is the appropriate choice for precise grade documentation. Both certificates verify the stone as laboratory-grown, confirm the exact carat weight, and provide the girdle inscription number for independent verification.

At StudsDirect, every stone is IGI certified with specific grades. Browse the collection — or read our guides on lab-grown diamond resale value and what VVS looks like under magnification.