When you're buying a diamond, the grading report is the closest thing the stone has to a résumé. It tells you – independently, in writing – exactly what you're getting: the cut, color, clarity, carat weight, and how it was grown. Without one, you're taking the seller's word for it. With one, you know.

Two names dominate diamond grading: GIA (the Gemological Institute of America) and IGI (the International Gemological Institute). If you're shopping for a lab-grown diamond, you'll run into both. Here's how they compare and what to look for on the report.

What Certification Actually Tells You

A grading report from a respected lab confirms the diamond's 4Cs, its measurements and proportions, and – crucially for lab-grown stones – the method used to grow it (HPHT or CVD) and a clear statement that the diamond is laboratory-grown. That disclosure is required, and any legitimate seller provides it without being asked.

IGI: The Lab-Grown Standard

IGI has graded lab-grown diamonds for years using the full 4Cs scale, and today it issues more lab-grown grading reports than any other lab. If you buy a certified lab-grown diamond, there's a good chance the report in the box says IGI. Their grading is consistent, their reports are detailed, and the trade knows them well.

GIA: The Heavyweight, Now Fully in the Game

GIA is the lab that created the 4Cs grading system the whole industry uses, and for decades it was the gold standard primarily for natural diamonds. GIA now grades lab-grown diamonds on the same color and clarity scales as mined stones, so a GIA-graded lab-grown diamond carries the same rigorous evaluation GIA is known for.

So Which Report Is Better?

Honestly? For a lab-grown diamond, a report from either lab is a strong sign you're dealing with a legitimate stone from a legitimate seller. IGI reports are more common in the lab-grown market, which also means more price competition and better value for you. GIA reports carry the GIA name premium some buyers prefer.

What matters far more than the logo at the top is that the report exists, comes from an independent lab, and matches the stone you're buying.

What to Check on the Report Before You Buy

·       “Laboratory Grown” disclosure – stated clearly on the report, never buried.

·       Growth method – HPHT or CVD. Both produce beautiful diamonds; the report should say which one.

·       Inscription – most certified lab-grown diamonds have a microscopic laser inscription on the girdle with the report number. A jeweler can show it to you under magnification.

·       The full 4Cs – cut, color, clarity, and carat weight, each with its own grade.

Does the Lab Change the Price?

Sometimes, slightly. Stones with GIA reports can carry a small premium because of the name. But the diamond itself – its beauty, its grades – is what you're really paying for. A gorgeous IGI-certified stone will out-sparkle a mediocre GIA-certified one every time. Grades first, logo second.

Why We Only Recommend Certified Stones

An uncertified diamond might be beautiful, but you'd never know if you overpaid. Certification removes the guesswork, protects resale and insurance value, and – just as important – it holds the seller accountable. Our graduate gemologists walk every customer through the actual report, line by line, before anything is finalized.

Frequently Asked Questions

Is IGI certification legitimate?

Yes. IGI is one of the world's major gemological laboratories and the most experienced grader of lab-grown diamonds. Its reports are accepted throughout the jewelry trade.

Does GIA certify lab-grown diamonds?

Yes. GIA grades lab-grown diamonds using the same color and clarity scales it uses for natural diamonds, with clear laboratory-grown disclosure on every report.

Should I avoid uncertified lab-grown diamonds?

We recommend against it. Without an independent grading report, you have no verified record of the diamond's quality – which makes fair pricing, insurance, and future resale much harder.

How can I verify the report matches my diamond?

Check the laser inscription on the diamond's girdle against the report number. Any reputable jeweler will do this with you under magnification at the time of purchase.

Will Jae's Jewelers explain my diamond's grading report?

Absolutely – it's one of our favorite parts of the job. Visit our Coral Gables showroom and our graduate gemologists will walk you through every line of the report and show you exactly what each grade means in the stone itself.