ELMONAS / EDUCATION
Grading lab-grown diamonds: IGI vs GIA
The short answer
IGI grades lab-grown diamonds on the full 4Cs scales; since 1 October 2025, GIA describes colorless lab-grown diamonds as Premium or Standard.
What is the short answer?
IGI grades lab-grown diamonds on the full 4Cs scales, with color graded D to Z and clarity graded IF to I. Since 1 October 2025, GIA no longer applies D-to-Z grading to colorless lab-grown diamonds; it issues a Laboratory-Grown Diamond Quality Assessment that describes a stone as "Premium" or "Standard".
Both documents identify the stone as a lab-grown diamond. Older GIA laboratory-grown diamond reports, issued with color and clarity grades, remain valid.
How does IGI grade lab-grown diamonds?
IGI grades lab-grown diamonds with the same structure it uses for natural diamonds: the 4Cs. IGI has graded lab-grown diamonds since 2005.
| Element | What the IGI report shows |
|---|---|
| Color | D to Z scale (D-F colorless, G-J near colorless, K-M slightly tinted, N-P very light, S-Z light, plus Fancy) |
| Clarity | IF, VVS1-2, VS1-2, SI1-2, I1-3 |
| Cut | Cut grade for round brilliants, based on proportions compared with IGI studies of brightness, fire and scintillation; fancy shapes assessed through a four-step system |
| Polish and symmetry | Graded for all shapes and colors |
| Growth process | HPHT or CVD may be included in the report comments, in some cases |
| Treatments | Disclosed when present |
| Inscription | Girdle laser inscription of the report number is available (IGI Laserscribe) |
How does GIA assess lab-grown diamonds today?
GIA's Laboratory-Grown Diamond Quality Assessment, launched 1 October 2025, describes a colorless lab-grown diamond as "Premium" or "Standard" based on an overall assessment of clarity, color and cut. A stone that does not meet all of the minimum "Standard" criteria does not receive a GIA assessment.
| Criterion | Premium | Standard |
|---|---|---|
| Color | D | E to J |
| Clarity | Very, Very Slightly Included and higher | Very Slightly Included |
| Polish | Excellent | Very Good |
| Symmetry | Excellent | Very Good (Good for fancy shapes) |
| Cut grade (round brilliants only) | Excellent | Very Good |
Each assessed stone's girdle is laser-inscribed with "Laboratory-Grown" and the GIA assessment number, and a printed document with the results is returned with the stone. The minimum size for submission is 0.15 carats.
Why did GIA change its format?
GIA's stated reason is that more than 95 percent of laboratory-grown diamonds entering the market fall into a very narrow range of color and clarity, so the nomenclature developed for the wider range of natural diamonds is no longer a relevant way to describe a manufactured product.
GIA continues to accept lab-grown diamonds for evaluation and identification. IGI continues to grade lab-grown diamonds on the D-to-Z and clarity scales.
How do the two documents compare?
| IGI Laboratory Grown Diamond Report | GIA Laboratory-Grown Diamond Quality Assessment | |
|---|---|---|
| In use since | 2005 | 1 October 2025 |
| Color description | D to Z grades | Premium or Standard category |
| Clarity description | IF to I grades | Premium or Standard category |
| Cut grade | Yes (round brilliants) | Only within the Premium or Standard criteria (round brilliants) |
| Growth method | May be included in report comments, in some cases | n/a (not stated in GIA's announcement) |
| Origin statement | Identifies the stone as lab-grown | "Laboratory-Grown" inscription plus assessment document |
| Verification | IGI online report verification | GIA Report Check |
What about GIA lab-grown reports issued before October 2025?
They remain valid. GIA confirmed that existing GIA reports for laboratory-grown diamonds stay valid after the change, so a stone with an older GIA report carrying D-to-Z grades has a legitimate document.
Which report comes with an Elmonas stone?
Every stone has an IGI or GIA report, and the report number appears with the stone on the availability list. Verify it with the lab before you buy; the steps are in How to read and verify a report.
Where can I see lab-grown diamonds?
- Lab-grown diamonds with IGI reports
- Lab-grown diamonds with GIA reports
- Round lab-grown diamonds
- Ask for today's list on WhatsApp
Sources
- IGI, Laboratory Grown Diamond Report: https://www.igi.org/reports/lab-grown-diamond-report/
- GIA press release, GIA Launches Updated Laboratory-Grown Diamond Services October 1 (Premium and Standard criteria): https://www.gia.edu/gia-news-press/updated-laboratory-grown-diamond-services-to-launch-october-1
- GIA press release, GIA to Use New Descriptive Terminology for Laboratory-Grown Diamonds (reason for the change, existing reports remain valid): https://www.gia.edu/gia-news-press/new-descriptive-terminology-for-laboratory-grown-diamonds
Last reviewed: 18 October 2026
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