IGI vs GIA for Lab Grown Diamonds: What Each Report Tells You
IGI and GIA are the two best-known independent gem labs, and both issue reports for lab grown diamonds. Since late 2025 their reports look quite different. IGI still grades lab grown diamonds on the full color and clarity scales. GIA no longer does: its lab grown report now confirms the diamond is lab grown and places it in a "premium" or "standard" category. Here is what each report tells you, how to check one, and when a report is worth having.
The short version
| IGI | GIA (since late 2025) | |
|---|---|---|
| Confirms the diamond is lab grown | Yes | Yes |
| Color grade (D to Z) | Yes | No; a broad category instead |
| Clarity grade (FL to I) | Yes | No; a broad category instead |
| Quality wording | Full 4Cs grades | "Premium" or "standard", or no designation if below the minimum |
| Measurements and carat weight | Yes | Yes |
| Laser inscription on the girdle | Usually | Yes |
| Share of lab grown reports | The majority (about 65% by its own 2024 figures) | Much smaller |
What changed at GIA
On June 2, 2025, GIA announced that it would stop using its natural-diamond color and clarity terms for lab grown diamonds. Its reasoning, in the words of GIA's chief laboratory officer Tom Moses: "More than 95% of laboratory-grown diamonds entering the market fall into a very narrow range of color and clarity." The new service began in the autumn of 2025. GIA lab grown reports now say whether a stone is "premium" or "standard", based on a mix of color, clarity and finish, and stones below the minimum receive no designation. Older GIA lab grown reports with full grades remain valid.
What an IGI report shows
IGI grades most of the world's lab grown diamonds and has kept the familiar 4Cs format: color, clarity, cut (for round brilliants) and carat, plus measurements, proportions and a report number that is usually laser-inscribed on the stone. IGI reports also commonly note the growth method and whether the diamond has had treatment after growth, which is common with CVD diamonds. Read CVD vs HPHT for what that means.
Which is better?
- If you want exact grades to compare stones side by side, an IGI report gives more detail.
- If you want a simple quality band from the lab best known for natural diamonds, a GIA report gives that.
- Compare like with like. Grading practice can differ slightly between labs, so compare prices between stones graded by the same lab.
How to check any grading report
- Type the report number into the lab's own website, rather than relying on a printed QR code or a PDF.
- Check that the measurements and carat weight online match the stone you are buying.
- Ask the jeweler to show you the laser inscription on the girdle under a loupe, and check it matches the report number.
- Make sure the report says "laboratory-grown". A lab grown diamond should never be sold as natural.
Do you need a report?
A report is most useful for larger or more expensive stones, for insurance, and when you compare stones from different sellers. It adds to the cost, and it does not make a lab grown diamond hold its value, since lab grown diamonds resell for little. See are lab grown diamonds worth it? and our lab grown diamond price guide.
What we provide at Bhumi Gems
Every Bhumi Gems piece comes with our own certificate of authenticity stating the stone, carat and metal. Independent lab reports are not included. Our lab grown diamond listings give E-F color and VVS clarity for the centre stone. If an independent report matters to you, for example for insurance, ask us before you order and we will tell you what is possible for your stone.
What about moissanite?
Moissanite is not a diamond, so it is not graded on these diamond reports. Moissanite cards, such as GRA cards, are issued within the moissanite trade rather than by independent labs. Read moissanite grades and GRA certificates.
Quick answers
Is IGI or GIA better for lab grown diamonds?
Both are respected independent labs. IGI gives full color and clarity grades for lab grown diamonds; GIA now gives a broader premium or standard category.
Does GIA still grade lab grown diamonds?
Yes, but since late 2025 it no longer uses D-to-Z color or clarity grades for them. Its reports confirm the stone is lab grown and give a quality category.
Why are most lab grown diamonds graded by IGI?
IGI grades lab grown diamonds with the full 4Cs and in large volumes, and by its own 2024 figures it handles about two thirds of lab grown diamond reports.
How do I check a lab grown diamond report?
Enter the report number on the lab's website and match it with the laser inscription on the stone.
Sources: GIA press release, June 2, 2025; trade reports in JCK, National Jeweler and Rapaport; IGI's 2024 share-offer documents as reported by National Jeweler.