When you buy a lab-grown diamond, one of the most important things to look for — right alongside cut, color, and clarity — is certification. Specifically, IGI certification. If you've seen the acronym and weren't sure what it means, this guide will explain everything you need to know.
What Is IGI?
IGI stands for the International Gemological Institute. Founded in 1975 and headquartered in Antwerp, Belgium, IGI is one of the world's largest and most respected independent diamond grading laboratories. They operate grading facilities in Antwerp, New York, Mumbai, Hong Kong, Tokyo, Dubai, and beyond — and have issued hundreds of millions of gemological reports over the past five decades.
IGI grades diamonds on the same 4 Cs system used by GIA (Gemological Institute of America): cut, color, clarity, and carat weight. Each certified diamond receives a unique report number that can be verified directly on the IGI website.
Why IGI Is the Standard for Lab-Grown Diamonds
While GIA has long been considered the gold standard for natural diamond certification, IGI has established itself as the leading authority for lab-grown diamonds. IGI was one of the first major labs to develop robust, standardized grading protocols specifically for lab-grown stones — and the industry has recognized this leadership.
Today, the majority of lab-grown diamonds sold by reputable jewelers worldwide come with IGI certification. When you see "IGI Certified" on a lab-grown diamond, you're seeing a meaningful quality assurance — not just a marketing label.
What an IGI Report Tells You
Each IGI diamond report includes the stone's precise measurements, carat weight, shape and cutting style, color grade, clarity grade, and cut grade (for round brilliants). It also includes a clarity diagram mapping the location of any inclusions, and — critically for lab-grown diamonds — it specifies the growth method used (HPHT or CVD) and confirms that the stone is laboratory-grown rather than mined.
This transparency is exactly what makes the report so valuable. You know precisely what you're getting.
IGI vs. GIA: What's the Difference?
Both are highly reputable grading laboratories. GIA pioneered the 4 Cs grading system and remains the most recognized name in natural diamond certification. IGI has built equivalent expertise in the lab-grown space. For lab-grown diamonds specifically, IGI reports are widely considered the industry benchmark — and many in the trade regard IGI's lab-grown grading as equally rigorous to GIA's natural diamond work.
When comparing IGI-graded lab-grown diamonds, you may also notice they're slightly more generously graded than equivalent GIA-graded natural stones. This is normal and expected within the industry.
Why We Require Certification on Every Diamond We Sell
At Atelier Diamante, every lab-grown diamond we offer is accompanied by an IGI certificate. We require this not because it's standard practice — though it increasingly is — but because we believe our clients deserve independent, third-party verification of exactly what they're purchasing. A certificate is not a formality; it's accountability.
When you buy a certified diamond from us, you receive a copy of the grading report alongside your piece — a permanent record of your stone's quality that you can reference, insure against, and pass on. Have questions about certification? We're happy to walk you through it.