CERTIFICATION
What a diamond certificate tells you.
A grading report from an independent gemological laboratory describes a diamond's measurable characteristics. It is the common language buyers and retailers use to compare stones.
What is on the report
Carat weight, color grade, clarity grade, cut grade where the lab gives one, shape and measurements, and a unique report number. Lab-grown diamonds are identified as laboratory-grown on their reports.
What it does not tell you
A report does not give a price or an appraisal value, and it does not describe a retailer's return policy, service or delivery. Two stones with the same grades can still look different to the eye, so view a stone, or its photos and video, before you buy.
Common laboratories
GIA
Gemological Institute of America. Widely used for natural diamonds.
IGI
International Gemological Institute. Widely used for laboratory-grown diamonds.
AGS
American Gem Society. Known for its detailed cut grading.
Laboratories use different grading standards, so the same grade from two labs is not always identical.
Verify before you buy
Match the report number on the certificate to the laboratory's own online report check, and ask the retailer whether the stone is laser-inscribed with that number.
How GemSeeker.ai uses certification
Our comparisons show each listing's certification so you can compare stones graded by the same laboratory.