GIA vs IGI for Lab-Grown Diamonds: 2026 Retailer Guide
GIA vs IGI for Lab-Grown Diamonds: What Retailers Need to Know
Quick answer: As of 1 October 2025, GIA no longer issues 4Cs grades for lab-grown diamonds. Stones now receive only a "Premium" or "Standard" quality assessment, or no report at all. IGI, which certifies roughly 65% of lab-grown diamonds globally, continues to issue full colour, clarity, and cut grades. For any retailer who needs to price, compare, or describe a stone by specification, IGI is now effectively the only mainstream option.
What changed on 1 October 2025
GIA announced in June 2025 that it would stop applying the 4Cs to lab-grown diamonds, and the change took effect on 1 October 2025 (GIA press release). Traditional 4Cs grading for lab diamonds ended on 30 September 2025.
GIA's stated reasoning, from executive vice president and chief laboratory and research officer Tom Moses, is that more than 95% of lab-grown diamonds entering the market fall into a very narrow range of colour and clarity, which makes the nomenclature developed for natural diamonds no longer relevant for describing them.
Under the new GIA system:
| GIA assessment | Criteria |
|---|---|
| Premium | D colour, VVS clarity or higher, Excellent polish, symmetry, and cut (round brilliant) |
| Standard | E to J colour, VS clarity or better, Very Good polish, symmetry, and cut |
| No designation | Stones below the Standard threshold receive no GIA report |
Reports cost $15 per carat with a $15 minimum. Stones that fail assessment are charged a $5 evaluation fee and receive nothing.
Reports issued before 1 October 2025 remain valid, so pre-October GIA lab-grown stock still carries full 4Cs grades. If you are buying GIA-certified lab-grown inventory, check the report date.
What this means for a wholesale buyer
The practical consequence is straightforward. A GIA report on a post-October-2025 lab-grown stone tells you it is "Premium" or "Standard". It does not tell you the colour grade, the clarity grade, or the cut grade. You cannot price a parcel on specification, compare two stones within a tier, or describe the stone to your customer in the language they expect.
IGI, GCAL, and HRD Antwerp all continue to issue full 4Cs reports for lab-grown diamonds. Of those, IGI is the volume standard.
Where IGI stands
IGI holds roughly 65% of the global lab-grown certification market, per its own management and independent analysis. It was founded in 1975 in Antwerp and was the first major laboratory to offer full grading reports for lab-grown diamonds, in 2005, well before the category scaled.
| Factor | IGI | GIA (post-Oct 2025) |
|---|---|---|
| Lab-grown 4Cs grading | Yes, full colour, clarity, cut | No |
| What the report tells you | Specific grades, clarity plot, polish, symmetry, fluorescence | Premium, Standard, or nothing |
| Growth method disclosure | Explicit CVD/HPHT notation | Laser inscription noting laboratory-grown |
| Lab-grown market share | Roughly 65% | Minority and now reduced by the change |
| Cost | Lower | $15 per carat, $15 minimum |
| Founded | 1975, Antwerp | 1931 |
What to check on any lab-grown certificate
Report date. A GIA lab-grown report dated before 1 October 2025 carries 4Cs. After that date it does not.
Growth method. The report should state CVD or HPHT.
Clarity plot. A plotted diagram, not just a stated grade.
Online verification. Confirm the report number on the issuing lab's own portal before paying.
How LabGems supplies
We supply both IGI-certified and non-certified lab-grown diamonds from the Antwerp Diamond District. Certified stones carry a full IGI report and suit centre stones and higher-value pieces where your customer expects independent grading. Non-certified goods price lower and suit melee, accent stones, and volume work.
| Term | Detail |
|---|---|
| Goods | IGI-certified and non-certified |
| Pricing | Published in EUR |
| Minimum order | €500 combined |
| Dispatch | In-stock ships within 1 business day, delivery 1 to 3 days |
| Payment terms | Net-30 / Net-60 for approved accounts |
Request wholesale pricing and we will quote against live inventory within one business day.
FAQ
Does GIA still grade lab-grown diamonds?
Not with the 4Cs. Since 1 October 2025, GIA issues only a "Premium" or "Standard" quality assessment for lab-grown diamonds, or no report if the stone falls below the Standard threshold. Reports issued before that date remain valid and carry full grades.
Is IGI or GIA better for lab-grown diamonds in 2026?
For any buyer who needs colour, clarity, and cut grades, IGI is now effectively the only mainstream choice, as GIA no longer issues them for lab-grown. IGI certifies roughly 65% of lab-grown diamonds globally.
Why did GIA stop using the 4Cs for lab-grown diamonds?
GIA states that more than 95% of lab-grown diamonds fall into a very narrow range of colour and clarity, making fine gradations less useful for differentiating stones.
Does LabGems only sell certified diamonds?
No. We supply both IGI-certified and non-certified lab-grown diamonds.
