IGI-Certified Diamonds Explained
An IGI certificate is an independent grading report for a diamond. Here's what it covers and how we use it.
Quick answer
IGI (the International Gemological Institute) is an independent laboratory that grades diamonds and issues a grading report — often called a certificate — describing a stone's carat, cut, colour and clarity. At Majestic, lab-grown diamonds are graded by IGI, while natural diamonds are graded by GIA or HRD, so every diamond is independently verified.
What IGI certification is
IGI is one of the world's established gem laboratories. When a diamond is submitted, trained graders assess it under controlled conditions and issue a report recording its measurements and the 4Cs — carat, cut, colour and clarity — along with a unique report number. Because the lab is independent of the seller, the report gives you an objective description rather than the retailer's own opinion.
What's on the report
| Section | What it tells you |
|---|---|
| Carat weight | The exact weight to two decimal places. |
| Cut / shape | The shape and, for round brilliants, the cut grade. |
| Colour | Position on the D-Z scale. |
| Clarity | Grade from FL to I3, often with a plotted diagram. |
| Measurements | Dimensions in mm, plus polish and symmetry. |
| Report number | A unique ID, sometimes laser-inscribed on the girdle. |
How we grade our diamonds
Our approach is simple and consistent: lab-grown diamonds are independently graded by IGI, and natural diamonds by GIA or HRD. Whichever you choose, you receive a stone described on a recognised, independent report — not an in-house estimate. If you're weighing up the two, the lab-grown vs natural guide explains the difference.
Buying a certified diamond
Because every diamond comes with an independent grading report and is then set to your size, you know exactly what you're buying. Message our team on WhatsApp and we'll help you choose.
Frequently asked questions
What does IGI-certified mean?
It means an independent laboratory, the International Gemological Institute, has graded the diamond and issued a report describing its carat, cut, colour and clarity with a unique report number.
Do you grade natural and lab-grown diamonds the same way?
We use IGI for lab-grown diamonds and GIA or HRD for natural diamonds. All are recognised independent laboratories, so every diamond is objectively graded.
Is an IGI report the same as a valuation?
No. A grading report describes the diamond's quality; it is not an insurance valuation. We can advise on arranging a separate valuation if you need one for cover.
Can I see the report before buying?
Yes. Because each diamond is selected for your ring, we share the grading details so you can confirm the stone before it's set to your size.