You've found a lab grown diamond you love. The price looks right. The ring is beautiful. But before you buy, there's one thing that matters more than anything else: the certificate.
In India's fast-growing lab grown diamond market, the IGI certificate is your single most important protection as a buyer. It tells you exactly what you're gettingand gives you the confidence to compare, negotiate, and invest wisely.
Here's how to read it, what every grade means, and what to watch out for.
What Is IGI?
The International Gemological Institute (IGI) is the world's largest independent gemological laboratory, with offices in Antwerp, New York, Mumbai, and across Asia. It is the leading certification authority for lab grown diamonds globallyand the most widely recognised by jewellers and resellers in India.
While GIA (Gemological Institute of America) is the gold standard for mined diamonds, IGI has established itself as the definitive authority for lab grown stones. When you see "IGI Certified" on a lab grown diamond listing, you're looking at the most credible grading available.
Breaking Down the 4Cs on Your IGI Report
Every IGI certificate grades your diamond on the four internationally recognised quality criteriathe 4Cs. Understanding each one helps you make a smarter purchase.
1. Cut
Cut is the most important of the 4Cs. It determines how well the diamond reflects lightits brilliance, fire, and scintillation. IGI grades cut as Excellent, Very Good, Good, Fair, or Poor. Always aim for Excellent or Very Good. A poorly cut 1-carat diamond will look duller than a well-cut 0.7-carat stone.
2. Colour
Diamond colour is graded on a scale from D (colourless) to Z (light yellow or brown). For white diamonds, D–F is colourless, G–J is near-colourless (and excellent value), and K onwards shows visible warmth. For lab grown diamonds, G–H is the sweet spotvisually colourless to the naked eye at a significantly lower price than D–F.
3. Clarity
Clarity measures internal inclusions and external blemishes. The IGI scale runs from FL (Flawless) to I3 (Included). For lab grown diamonds, VS1–VS2 (Very Slightly Included) offers the best balance of quality and valueinclusions are invisible to the naked eye but the price is far lower than FL or IF grades.
4. Carat
Carat is the weight of the diamond (1 carat = 0.2 grams). Larger carat weights command exponentially higher pricesa 2-carat diamond is not twice the price of a 1-carat, it's typically 3–4x more. Lab grown diamonds let you access higher carat weights at prices that would be impossible with mined stones.
What "Type IIA" Meansand Why It Matters
Many IGI certificates for lab grown diamonds include a Type IIA designation. This refers to the chemical purity of the diamondType IIA diamonds contain virtually no nitrogen impurities, making them the chemically purest form of diamond. Most of the world's most famous diamonds (including the Cullinan and Koh-i-Noor) are Type IIA.
The majority of CVD lab grown diamonds are Type IIAa quality characteristic that is actually rarer in mined diamonds (only ~1–2% of natural diamonds qualify). It's a meaningful quality indicator, not just marketing language.
How to Verify Your IGI Certificate Online
Every IGI certificate has a unique report number. You can verify it instantly at igireport.igi.orgenter the report number and the full grading details will appear. This is the simplest way to confirm a certificate is genuine and hasn't been altered.
At Unii Jewels, every diamond comes with a verifiable IGI certificate. We encourage you to check yours the moment it arrives.
Red Flags: What to Watch For
Not all lab grown diamond sellers operate with the same transparency. Watch out for:
- No certificate, or a certificate from an unknown labonly IGI and GIA carry meaningful weight for lab grown diamonds in India
- Certificate grades that don't match the listingalways cross-reference the report number online
- "IGI Pending" listingsa diamond without a current certificate is ungraded; don't pay certified prices for it
- Unusually low prices for high gradesan Excellent cut, D colour, FL clarity 1-carat at a suspiciously low price warrants scrutiny
Shop with Confidence
Every diamond in the Unii Jewels collection is independently graded and certified by IGI before it reaches you. You'll receive the physical certificate with your order and can verify every detail online.
