GIA's New Lab-Grown Diamond Grading: What Changed

• IGI-certified diamonds
• Triple Excellent standard
• Lifetime setting upgrades
• Free, fully insured shipping
• Made to order in Toronto

On October 1, 2025, GIA stopped issuing specific colour and clarity grades for lab-grown diamonds and replaced them with a two-tier label: Premium or Standard. IGI, the laboratory that certifies the large majority of lab-grown diamonds on the market, made no such change — it continues to grade lab-grown stones on the full D-to-Z colour scale and FL-to-I3 clarity scale, the same system used for mined diamonds. If you're shopping against a precise standard, that gap between the two labs now matters more than it did a year ago.

Key takeaways

• GIA replaced individual 4Cs grading for lab-grown diamonds with a printed "Laboratory-Grown Diamond Quality Assessment" that shows only a Premium or Standard classification.
• "Premium" requires D colour and VVS clarity or higher, with Excellent polish and symmetry (plus an Excellent cut grade on round brilliants).
• "Standard" covers a much wider band — E to J colour, VS clarity, Very Good polish and symmetry, and at least a Very Good cut on round brilliants.
• Diamonds that fall below the Standard threshold receive no classification at all, though GIA still charges an assessment fee.
• IGI has reaffirmed it will keep grading lab-grown diamonds on the same full 4Cs scale it uses for mined diamonds — no bucketing.
• A two-letter label can't tell you if a stone is D or E colour, or VVS1 versus VVS2 — which is exactly the precision a fixed house standard like Montare's depends on.

What actually changed on October 1, 2025

Until late 2025, a lab-grown diamond graded by GIA received the same kind of report as a mined stone: a specific colour letter (D through Z) and a specific clarity grade (Flawless through Included), alongside cut, polish and symmetry. On October 1, 2025, GIA retired that approach for lab-grown diamonds and launched what it calls the Laboratory-Grown Diamond Quality Assessment — a printed document that carries a quality classification, an assessment number, and a girdle inscription reading "Laboratory-Grown" plus that number. What it no longer carries is the individual colour letter or clarity grade you'd see on a mined-diamond report, or on a lab-grown report from IGI.

The assessment applies to lab-grown diamonds of 0.15 carats and above. In practice, a GIA-assessed lab-grown diamond bought today is described in one of two words — Premium or Standard — rather than a specific point on the colour and clarity scales.

Worth being precise about what did not change: GIA continues to grade mined diamonds on the full 4Cs exactly as before, and it continues to identify lab-grown diamonds as lab-grown, both on the document and in the girdle inscription. Nothing about disclosure was weakened. What narrowed is the resolution of the quality information itself.

Premium vs Standard, at a glance

	Premium	Standard
Colour	D	E to J
Clarity	VVS or higher	VS
Polish	Excellent	Very Good
Symmetry	Excellent	Very Good (Good accepted on some fancy shapes)
Cut (round brilliants only)	Excellent	Very Good
Below these minimums	No classification issued

Notice what the table can't tell you: whether a "Premium" stone is D colour with VVS2 clarity or D colour with Flawless clarity — both qualify for the same label. The same is true across the whole "Standard" band, which spans four colour grades and one full clarity grade. For a general shopper comparing "good" to "better," that may be enough. For a standard as specific as Montare's D–E colour and VVS1–VVS2 clarity floor, it isn't.

Why did GIA make the change?

GIA's stated reasoning is a clustering argument: the overwhelming majority of lab-grown diamonds submitted for grading fall into a narrow band of colour and clarity, because CVD and HPHT growers can now produce very clean, near-colourless material as a matter of course. GIA president Pritesh Patel put it directly: descriptive terms are appropriate for lab-grown diamonds "as most fall into a very narrow range of color and clarity." The institute's broader point is that a scale built for the wide natural spread of mined diamonds — where a J-colour, I1-clarity stone and a D-colour, Flawless stone are both common — doesn't map cleanly onto a manufactured product that clusters tightly at the top of that same scale.

It's a defensible argument on its own terms. It's also a choice that trades precision for simplicity, and that trade lands differently depending on what you're trying to verify.

What this means if you're shopping for a lab-grown diamond

• You can no longer read an exact grade off a GIA lab-grown report. "Premium" could mean D/Flawless or D/VVS2 — the report doesn't distinguish, and the two are not the same stone.
• "Standard" is a wide net. E colour and J colour sit four grades apart and look meaningfully different face-up in larger stones; both now share one label.
• An unclassified stone isn't necessarily disclosed as lower quality — it simply receives no report, which makes it harder to compare against a competing offer that does carry a full grade.
• If a retailer quotes you a "GIA Premium" lab-grown diamond, ask directly what colour and clarity it actually is. The seller should know, even though the report itself won't spell it out letter-for-letter.

None of this reflects on the physical diamonds themselves — a lab-grown stone graded in September 2025 and one graded in November 2025 can be identical. What changed is how much of that information reaches you on paper.

IGI vs GIA for lab-grown, now

The two labs have effectively diverged on lab-grown reporting philosophy. IGI grades the large majority of lab-grown diamonds on the market and has reaffirmed that it will continue applying the full D-to-Z colour scale and FL-to-I3 clarity scale to lab-grown stones — the identical standard it uses for natural diamonds. GIA now applies its own scale only to natural diamonds, while lab-grown diamonds get the Premium/Standard treatment described above.

	IGI	GIA (post-Oct 2025)
Colour reporting	Specific letter, D–Z	Bucketed: D, or E–J
Clarity reporting	Specific grade, FL–I3	Bucketed: VVS+, or VS
Cut/polish/symmetry	Full grades	Full grades within the Premium/Standard tier
Lab-grown market share	Majority of lab-grown stones	Smaller share; entered lab-grown grading later

Neither approach makes a lab-grown diamond more or less real, or more or less durable — a lab-grown diamond is chemically, physically and optically identical to a mined one regardless of which lab wrote the report. The difference is purely in how much specification detail the paperwork gives you to verify against. For the fuller lab-by-lab breakdown, see IGI vs GIA for lab-grown diamonds.

How to verify a lab-grown report yourself

Whichever laboratory graded the stone, the verification steps are the same, and they take about two minutes:

1. Find the report or assessment number. It should be laser-inscribed on the diamond's girdle and printed on the document. A jeweller can show you the inscription under magnification.
2. Look it up on the laboratory's own website — not the retailer's. Both IGI and GIA host free public report lookup. The record that loads should match the document in your hand on every field.
3. Confirm the stone is named as laboratory-grown on the report. Legitimate documents from both labs state this plainly.
4. Read what the report actually specifies. On an IGI lab-grown report, that means a specific colour letter and clarity grade. On a post-2025 GIA assessment, it means a tier — so ask the seller for the underlying colour and clarity in writing.
5. Check the measurements against the carat weight. A well-cut stone's millimetre dimensions should be consistent with its weight; a stone that measures small for its carat is carrying weight in the pavilion rather than the face-up spread. Our guide to ideal table and depth covers the ranges.

A report of any kind verifies the diamond, not the price attached to it. That remains a separate question, and the more expensive one to get wrong — we run the arithmetic in what an $11,000 lab-grown ring is really charging you for.

Does this change the case for lab-grown diamonds?

Not materially. A lab-grown diamond is a real diamond — identical carbon lattice, identical hardness, identical optical behaviour — and that was true before October 2025 and remains true after. What GIA's change does is remove one layer of comparison detail from a subset of reports, which makes the choice of laboratory a more consequential part of a purchase than it used to be. If two sellers quote you a three-carat lab-grown diamond and one hands you a specific D/VVS1 grade while the other hands you the word "Premium," you are not looking at equally verifiable offers, even if the stones turn out to be identical.

The practical takeaway is unchanged from what it always was: buy from a seller who states the specification precisely and backs it with an independent report you can verify. That is a higher bar than it sounds, and it is the whole reason a fixed house standard exists.

Why Montare

Montare's floor is exact, not descriptive: lab-grown, D–E colour, VVS1–VVS2 clarity, Triple Excellent cut, ideal table and depth per shape, three carats minimum, IGI certified. That standard only means something if the report behind it can actually confirm a stone is D rather than E, or VVS1 rather than VVS2 — which is precisely the resolution GIA's new Premium/Standard system doesn't provide for lab-grown diamonds. It's why every Montare diamond carries an IGI report with the full colour and clarity grade stated, not a two-word tier. You can read the reasoning behind each part of the floor — why Triple Excellent matters and how clarity is actually graded — or see it applied to a real stone in the ring builder.

Frequently asked questions

Did GIA stop grading lab-grown diamonds?

No. GIA still assesses lab-grown diamonds — it changed what the report shows. Instead of a specific colour letter and clarity grade, lab-grown stones now receive a Premium or Standard classification, or no classification if they fall below the Standard thresholds.

Does this mean GIA-graded lab-grown diamonds are now lower quality?

No. The physical diamonds are unchanged — CVD and HPHT growing methods didn't change on October 1, 2025. Only GIA's reporting format changed, from a specific grade to a broader classification.

Can a "GIA Premium" lab-grown diamond still vary in quality?

Yes. Premium is a floor, not a fixed point — it covers D colour with VVS clarity through to D colour with Flawless clarity. Two stones both labelled Premium can sit at different points within that range.

Why does IGI still grade lab-grown diamonds on the full scale?

IGI has stated it will continue applying the same 4Cs rigor to lab-grown diamonds that it applies to natural diamonds, giving buyers a specific, comparable grade rather than a broad category.

Is a Montare diamond graded under GIA's new Premium/Standard system?

No. Every Montare diamond is IGI certified, with the full colour and clarity grade stated on the report — never a Premium/Standard label.

Does a Premium or Standard label affect how a lab-grown diamond looks?

No. A diamond's appearance is governed by its actual cut, colour and clarity — not by which label a report assigns it. The classification only affects how precisely that information is disclosed to you on paper.

Want to see the exact grade behind your diamond, not a tier label? Every stone in the ring builder carries a full IGI report, or book a consultation to talk it through with our Toronto team.

Sources: GIA's announcement of its Laboratory-Grown Diamond Quality Assessment (effective 1 October 2025), including the Premium and Standard criteria and the statement from GIA president Pritesh Patel, as reported by National Jeweler and Rapaport; and IGI's reaffirmation of 4Cs grading for all diamonds. Last reviewed August 2026.