If you are shopping for a lab-grown diamond, you will see IGI reports far more often than GIA, and you may have read that GIA "stopped grading" lab-grown diamonds. That is not quite right. GIA changed how it describes them in October 2025. Here is what each lab's report actually tells you, so you can compare stones with confidence.
IGI reports grade lab-grown diamonds on the familiar scales — carat, D-to-Z color, clarity, and cut for round brilliants — so you can compare stones in detail. Since October 1, 2025, GIA classifies them only as Premium or Standard. Either is fine; what matters is a verifiable report for the exact stone.
What changed at GIA in 2025?
In June 2025, GIA announced it would stop using the color and clarity nomenclature it developed for natural diamonds when describing lab-grown diamonds, saying most lab-grown stones on the market fall into a narrow range of color and clarity. Its revised service launched on October 1, 2025. The GIA Laboratory-Grown Diamond Quality Assessment covers loose, colorless to near-colorless lab-grown diamonds of 0.15 carats and up, and classifies each one as Premium or Standard based on clarity, color, polish, symmetry, and (for round brilliants) cut. The girdle is laser-inscribed with "Laboratory-Grown" and the assessment number.
- Premium requires all of: D color; VVS clarity or higher; Excellent polish and symmetry; and an Excellent cut grade for round brilliants.
- Standard covers stones that meet at least these minimums: E-to-J color; VS clarity; Very Good polish; Very Good symmetry (Good for fancy shapes); and a Very Good cut grade for round brilliants.
- A stone that falls below any Standard minimum — for example SI clarity or K color — does not receive a GIA assessment at all.
GIA has said existing reports remain valid, so you may still see older GIA lab-grown reports with letter grades. Colored lab-grown diamonds are covered by separate GIA reports.
What does an IGI lab-grown diamond report show?
IGI's Laboratory Grown Diamond Report uses the same grading scales buyers know from natural diamonds. It states that the stone is laboratory-grown and lists the shape and cutting style, measurements, carat weight, color on the D-to-Z scale, clarity assessed at 10x, a cut grade for round brilliants, and polish and symmetry for all shapes, along with fluorescence and proportions. Reports often note the growth method (HPHT or CVD) and whether there are indications of post-growth treatment. The report number is laser-inscribed on the girdle and can be verified on IGI's website. IGI also issues jewelry reports for stones that are already mounted.
IGI vs GIA: side by side
| IGI Laboratory Grown Diamond Report | GIA Laboratory-Grown Diamond Quality Assessment (from Oct 1, 2025) | |
|---|---|---|
| Color | D-to-Z letter grade | Not given as a letter grade; D required for Premium, E–J for Standard |
| Clarity | Full grade (e.g. VS1, SI1) | Not given as a grade; VVS+ for Premium, VS minimum for Standard |
| Cut | Cut grade for round brilliants; polish and symmetry for all shapes | Factored into the Premium/Standard result |
| Overall result | Individual grades | Premium, Standard, or no assessment |
| Stones below the thresholds | Still graded | No assessment (e.g. SI clarity, K color and below) |
| Growth method | Often noted (HPHT or CVD) | Check the specific report |
| Verification | Report number on girdle; look up on igi.org | Assessment number on girdle; look up on gia.edu |
Which report should I trust for an engagement ring?
Both labs are independent and both reports state clearly that the stone is lab-grown. The practical difference is detail. An IGI report lets you compare two G VS2 stones against a G SI1 stone; a GIA assessment tells you whether a stone cleared the Premium or Standard bar, which is a quick quality signal but does not separate, say, a VS1 from a VS2 or an E from an H. If you are optimizing for value — buying the lowest color and clarity that still look good — IGI's detail is more useful. If you simply want reassurance that a stone meets a defined quality floor, a GIA Standard or Premium result does that.
Either way, the report is only half the picture. Two stones with identical grades can look different, so ask for photos or video of the actual diamond, especially if you are aiming for an eye-clean stone. Our guide to choosing a lab-grown engagement ring explains which grades make a visible difference.
How do I verify a lab-grown diamond report?
- Find the report number on the paperwork.
- Check that it matches the laser inscription on the girdle (a jeweler's loupe or the seller's photos will show it).
- Look the number up on the issuing lab's website.
- Confirm the carat weight, measurements, and grades match the stone you are buying, and that it is described as laboratory-grown. Our diamond carat size chart shows what measurements to expect for each carat weight.
When does the lab name not matter much?
Honestly, for many buyers the IGI-vs-GIA question is less important than it looks. If the stone is eye-clean, well cut, and the report verifies, the lab name will not change how the ring looks on a hand. Where it does not help: no report can tell you how a stone will look in your chosen setting, and neither report says anything about resale value, which for lab-grown diamonds is very limited regardless of the lab. Do not pay a large premium for a lab name alone.
Ready to choose a stone? Set shape, carat, color, clarity, and cut in the BVDIY ring studio, or compare stone types in lab diamond vs natural vs moissanite.
Sources: GIA, "GIA to Use New Descriptive Terminology for Laboratory-Grown Diamonds" (June 2, 2025) and "GIA Launches Updated Laboratory-Grown Diamond Services October 1" (August 26, 2025); GIA Laboratory-Grown Diamond Services page and assessment criteria chart; IGI Lab Grown Diamond Report page (igi.org).