Understanding IGI certification
What an IGI certificate tells you, how to read it, and why Mercury & Sol certifies every lab-grown diamond through IGI.
What is IGI?
The International Gemological Institute is one of the world’s largest independent gemological laboratories, with offices in Antwerp, New York, Mumbai, Hong Kong, and other major cities. IGI grades diamonds using the same rigorous 4Cs framework developed by the industry: cut, color, clarity, and carat weight. Each stone receives a detailed report documenting its exact measurements and quality grades.
What the certificate tells you
| Section | What it covers |
|---|---|
| Shape & cut | The stone’s shape (round, oval, etc.) and cut quality grade |
| Measurements | Exact dimensions in millimeters and proportions |
| Carat weight | Weight to the hundredth of a carat |
| Color grade | D (colorless) through Z (light yellow/brown) |
| Clarity grade | FL (flawless) through I3 (included) — type and location of inclusions |
| Cut grade | Excellent, Very Good, Good, Fair, or Poor |
| Polish & symmetry | Surface finish and facet alignment grades |
| Fluorescence | None, Faint, Medium, Strong, Very Strong |
Why IGI for lab-grown?
IGI was one of the first major gemological institutes to embrace lab-grown diamond grading, applying the same standards used for mined stones. Their experience with lab-grown diamonds is extensive, and their reports are widely recognized by jewelers, insurers, and consumers worldwide.
Every Mercury & Sol lab-grown diamond comes with an IGI certificate. Lab-grown colored gemstones (sapphires, emeralds, rubies, alexandrite) are not individually certified — this is standard industry practice for colored stones, where quality is assessed by visual inspection.
How to verify your certificate
Every IGI report has a unique report number. You can verify any certificate by visiting the IGI website and entering the report number in their verification tool. The online record will match the physical certificate that accompanies your stone, confirming its authenticity and grades.
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