A diamond grading report (often called a certificate) is a document issued by an independent gemological laboratory that assesses and records a diamond's characteristics. At Grissom's, we carry certified diamonds from the world's most respected laboratories and believe every significant diamond purchase should come with certification.
Why Certification Matters
A grading report from a reputable, independent laboratory gives you an unbiased, expert evaluation of your diamond. It verifies the 4 C's — Cut, Color, Clarity, and Carat Weight — as well as fluorescence, proportions, polish, and symmetry. Certification protects you as a buyer and provides documentation for insurance purposes.
GIA — Gemological Institute of America
The GIA is widely considered the gold standard for diamond grading. GIA established the 4 C's grading system that the entire industry uses today. GIA grades are known for their consistency and strict standards, and a GIA report adds confidence and often measurable value to a diamond purchase. Grissom's carries a strong selection of GIA-certified diamonds.
AGS — American Gem Society
The AGS is highly respected, particularly for its cut grading system. AGS uses a 0–10 scale (0 being the best) and is one of the few labs that provides a detailed cut analysis for fancy shapes as well as rounds. AGS certified diamonds are an excellent choice for buyers who prioritize cut quality.
GCAL — Gem Certification & Assurance Lab
GCAL is known for its "Guaranteed" grading reports — they provide a money-back guarantee on their grades, which is unique in the industry. GCAL reports also include optical measurements of brightness, fire, scintillation, and spread, giving buyers an especially complete picture of a diamond's performance.
IGI — International Gemological Institute
IGI is one of the largest gemological labs in the world and is commonly used for lab-grown diamonds and diamonds sold through chain retailers. IGI grades are generally considered slightly less stringent than GIA, so when comparing prices, it is important to know which lab certified the stone.
EGL — European Gemological Laboratory
EGL reports are used by some retailers, but buyers should be aware that EGL grades have historically been considered less consistent than GIA or AGS. A stone graded SI1 by EGL may grade VS2 or lower by GIA. At Grissom's, we always make sure our customers understand what laboratory certified their diamond so there are no surprises.
A Note on Lab-Grown Diamond Certification
Lab-grown diamonds are also graded and certified using the same 4 C's system as natural diamonds. GIA and IGI both issue reports for lab-grown stones. If you're considering a lab-grown diamond, we're happy to walk you through the differences and help you decide what's right for you.
Have questions about a specific certificate or want to compare diamonds side by side? Visit our Fort Worth showroom or contact us — our team is always glad to help.