IGI vs GIA for Lab-Grown Diamonds: Which Certificate Should You Choose?

Choose IGI for most lab-grown diamonds. An IGI report still prints a specific colour grade, clarity grade and cut assessment, while GIA stopped doing that for lab-grown diamonds on 1 October 2025 and now gives them a single rating of Premium or Standard. If you want to know that your stone is an F colour VS1 rather than just "Standard", IGI is the report that tells you.

GIA is still a sound choice if you want the name and a stone that has cleared its bar, but it tells you less about the diamond in front of you. Both labs are independent, both laser-inscribe the stone, and both reports can be checked online, so the decision comes down to how much detail you want in writing.

The individual grades. Since October 2025, GIA's Laboratory-Grown Diamond Quality Assessment rolls colour, clarity and finish into one tier, while IGI's lab-grown diamond report still grades each factor on the same scales used for natural diamonds:

That missing detail matters when you compare stones. Two GIA "Standard" diamonds could be an E colour VVS2 and a J colour VS2, which look and price quite differently, and the assessment would not tell them apart. Two IGI reports would.

They are quality bands. GIA published the criteria in its August 2025 announcement, and a stone has to meet every Premium threshold to be Premium, or at least the Standard thresholds to be Standard:

A lab-grown diamond that falls short of Standard gets no GIA assessment at all. GIA charges US$15 per carat for the assessment, with a US$15 minimum and a US$5 fee for stones that are not assessed, and those fees are unchanged in its fee schedule effective 1 January 2026.

Premium is a high bar. Of the 5,265 lab-grown diamonds on our own stone feed in September 2026, all of them D to F colour and VS1 or better, only 1,225, or 23%, were D colour with VVS clarity, the colour and clarity that Premium needs before polish, symmetry and cut are even considered.

GIA reports issued for lab-grown diamonds before October 2025 still show full colour and clarity grades and remain valid, so a GIA report with colour and clarity letters on it is an older report.

Because most of them grade the same. When GIA announced the change in June 2025, Tom Moses, its chief laboratory and research officer, said that "more than 95% of laboratory-grown diamonds entering the market fall into a very narrow range of color and clarity", so the scales built to separate natural diamonds no longer did much work. GIA also said the change would help buyers understand how differently the two products come about.

That narrow range is easy to see in practice. Every stone on our feed sits between D and F colour and between VS1 and VVS1 clarity, and a report that only said "Standard" would describe most of them the same way.

Many jewellers say IGI grades about one colour or clarity grade more generously than GIA, a reputation built largely on natural diamond grading. For lab-grown diamonds there is no longer a like-for-like comparison to make, because GIA no longer issues colour and clarity grades for new lab-grown stones, and we could not find an independent published study measuring the gap on lab-grown diamonds.

In practice a one-grade difference matters less here than on a natural diamond. Between D and F colour and VS1 and VVS1 clarity, the stones look colourless and clean to the eye, and our 1 carat price chart shows those grades sit within a few hundred dollars of each other. The cut and the look of the actual stone in a video will tell you more than a one-letter debate about the report.

IGI moved early and grades at scale. IGI says it pioneered lab-grown diamond grading in 2005, and the filing for its initial public offering put its share of lab-grown diamond grading reports at 65%, as reported by JCK. With that much of the market graded by one lab, retailers list and price stones from IGI reports, which is why most lab-grown engagement rings you see online come with one. Every one of the 5,265 lab-grown diamonds on our feed carries an IGI report.

Not by much. The report fee is a small part of a lab-grown diamond's price: GIA's assessment on a 1 carat stone is US$15, while a 1 carat lab-grown diamond on our feed has a median price of $1,271. What moves the price is the stone itself, its shape, carat weight, colour and clarity, along with the retailer's margin. If an IGI stone and a GIA stone of similar quality are hundreds of dollars apart, the report is not the reason.

Match the inscription, then look the report up. Both labs laser-inscribe a number on the girdle, the thin edge around the widest part of the stone, and a jeweller can show it to you under a loupe or microscope. Enter that number on IGI's report verification page or GIA's Report Check, which is linked from GIA's laboratory-grown diamond services page, and make sure the shape, measurements and carat weight online match the diamond you are buying. A GIA-assessed stone should also read "Laboratory-Grown" on the girdle.

Our diamond certification guide walks through reading a report line by line, and are lab-grown diamonds GIA certified has the short answer on GIA's current service.

Does GIA still grade lab-grown diamonds?

Yes, but not on the 4Cs. GIA still accepts lab-grown diamonds of 0.15 carats and up, identifies them and classifies them as Premium or Standard, and stones below Standard are returned without an assessment. Our article on how GIA changed lab-grown diamond grading covers the change in more detail.

Which is better, IGI or GIA, for a lab-grown engagement ring?

IGI, for most people, because it gives you the individual grades you need to compare stones. GIA suits a buyer who values its name and is happy with a Premium or Standard rating instead of specific grades.

Who has the highest quality lab-grown diamonds?

No lab makes diamonds. IGI and GIA grade stones that growers produce, so quality belongs to each individual stone, not to the lab on the report. Compare the grades, the cut and a video of the stone itself.

Is an IGI certificate trusted in Australia?

Yes. IGI grades most of the world's lab-grown diamonds, including every stone we sell, and any IGI report number can be checked on IGI's website. Keep the report with your purchase invoice for insurance.

If you are choosing a stone now, browse our lab-grown diamond engagement rings, where every diamond comes with its IGI report.

Thanks for reading, Jared and Brie