IGI certificates explained
Every lab-grown diamond sold by Brilliani comes with an IGI certificate. Here is what that means, what it tells you, and how to verify it yourself.
One of the world’s most trusted gemological institutes
The International Gemological Institute (IGI) is one of the world’s largest and most trusted independent gemological institutes, with laboratories in Antwerp, New York, Mumbai, Hong Kong and more. An IGI certificate confirms that your stone is a real diamond (lab-grown or mined) and grades it across four standardised criteria known as the 4Cs.
Stone type: confirms genuine diamond (carbon)
Carat weight
Cut grade: Excellent, Very Good, Good
Colour grade: D (colourless) through Z (light yellow)
Clarity grade: FL (flawless) through I3 (included)
Measurements in mm
Shape and cutting style
Unique report number for independent verification
What the grades actually mean
How well the diamond is shaped and faceted. Affects brilliance more than any other factor. Always prioritise cut.
How colourless the stone is. D–F is colourless; G–J is near-colourless and the sweet spot for value.
The presence of internal inclusions. VS1–VS2 is excellent value, with inclusions not visible to the naked eye.
The weight of the stone. Larger carat means larger stone, but cut quality determines how it actually looks.
“An IGI certificate doesn’t just tell you what you’re buying. It tells you exactly what grade you’re buying. That’s the difference between trust and assumption.”
Check it yourself
Your IGI report number is included with your order. Enter it at igionline.com to pull up the full grading report. Every detail on the certificate should match what you see on screen.
Graded by exactly the same criteria
Lab-grown diamonds are chemically and physically identical to mined diamonds. The IGI grades them using exactly the same criteria. The only difference noted on the certificate is the origin: laboratory-grown.