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For a lab-grown diamond, IGI and GIA reports are no longer comparable documents. Since 1 October 2025, GIA has stopped issuing specific colour and clarity grades on lab-grown diamonds, replacing them with a two-tier Premium or Standard classification. IGI continues to grade lab-grown stones on the full 4Cs, exactly as it does mined diamonds. Both laboratories remain independent and rigorous — but only one of them still tells you whether a stone is D or E, VVS1 or VVS2.
For lab-grown diamonds, an IGI certificate is the industry standard and grades cut, colour and clarity to the rigour you need. GIA grades lab-grown too, but IGI certifies the vast majority of lab stones and is what you'll see most. What matters is independent certification — every Montare diamond is IGI-certified.
- Key takeaways
- What are IGI and GIA?
- What changed on 1 October 2025?
- What do Premium and Standard actually mean?
- Why this matters if a seller states a specific grade
- IGI vs GIA for lab-grown, at a glance
- Does this make GIA the lesser laboratory?
- Does the laboratory cut-grade fancy shapes?
- What to read on the certificate
- The trap a certificate does not protect you from
- Why Montare specifies IGI
- Frequently asked questions
Key takeaways
- GIA changed its lab-grown reports on 1 October 2025 — no more D-to-Z colour or specific clarity grades.
- In their place: a two-tier Premium or Standard quality assessment.
- IGI still grades lab-grown on the full 4Cs, and has confirmed it will continue to.
- A two-word tier cannot verify a specific grade — Standard spans everything from E to J.
- This is not a claim that GIA is the lesser laboratory. It is not. The difference is resolution, not rigour.
- Every Montare diamond is IGI certified at the house floor: D–E, VVS1–VVS2, Triple Excellent, three carats minimum.
What are IGI and GIA?
The International Gemological Institute (IGI) and the Gemological Institute of America (GIA) are independent laboratories that grade diamonds. Neither mines, sells, nor sets stones. They exist to put an objective assessment on a diamond so that you are not taking the seller's word for it — because a diamond with no independent report is, in practice, a diamond graded by the person trying to sell it to you.
GIA is the older and more storied institution: it invented the modern grading framework, coining the 4Cs in the early 1940s and introducing the D-to-Z colour scale in 1953. IGI, founded in 1975, moved early and decisively into lab-grown grading and now certifies the large majority of lab-grown diamonds on the market. If the underlying grades are new to you, start with the 4Cs explained without jargon.
What changed on 1 October 2025?
GIA stopped applying its own D-to-Z colour scale and its specific clarity grades to laboratory-grown diamonds. Reports issued from that date carry a Laboratory-Grown Diamond Quality Assessment instead: an assessment number, a "laboratory-grown" girdle inscription, and a single two-tier classification — Premium or Standard.
GIA's stated reasoning, from president Pritesh Patel, is that more than 95% of the lab-grown diamonds submitted to it cluster within a narrow band of colour and clarity, so a scale built for the much wider natural spread of mined diamonds is not the right descriptive tool. That is a defensible position, and it is worth saying plainly that disclosure was not weakened by the change — origin is still stated, still inscribed. What was reduced is the resolution of the quality information.
IGI, for its part, has publicly reaffirmed that it will continue grading lab-grown diamonds on the full 4C framework — the same D-to-Z colour scale, the same FL-to-I3 clarity scale, and the same separate cut, polish and symmetry grades used for mined stones. We covered the change and the reaction to it in GIA's new lab-grown grading, explained.
What do Premium and Standard actually mean?
The two tiers are defined by thresholds across the same underlying attributes, collapsed into one word. This is what each covers.
| Attribute | Premium | Standard |
|---|---|---|
| Colour | D | E to J |
| Clarity | VVS or higher | VS |
| Polish | Excellent | Very Good |
| Symmetry | Excellent | Very Good |
| Cut (round brilliants) | Excellent | Very Good |
A stone falling below the Standard thresholds receives no classification at all. And note what the Standard tier contains: a genuinely colourless E sits in the same box as a J, which is four grades into the near-colourless band and visibly warmer at three carats. Two stones with materially different appearances and materially different market values carry the identical word on the paperwork.
Why this matters if a seller states a specific grade
It comes down to simple arithmetic. If a retailer's stated standard is "D–E colour, VVS1–VVS2 clarity", the report has to be capable of confirming those grades. A Premium classification tells you the stone is D and VVS or better — which does confirm a D, but cannot distinguish D from E, or VVS1 from VVS2. A Standard classification tells you the stone is somewhere between E and J with VS clarity — which cannot confirm the floor at all.
So the question to ask is not "is this lab reputable?" — both are. It is: does this report state the grade the seller is promising me? For a lab-grown stone bought on a specific specification, only a report carrying specific grades can answer that. That is the entire reason Montare specifies IGI certification rather than treating the two reports as interchangeable.
Every claim here is one you can check on the certificate — and we will walk you through a real one, no obligation.
Ask us anythingIGI vs GIA for lab-grown, at a glance
| IGI | GIA (from 1 Oct 2025) | |
|---|---|---|
| Independence | Fully independent | Fully independent |
| Colour on lab-grown | Full D-to-Z grade | Premium or Standard tier only |
| Clarity on lab-grown | Full FL-to-I3 grade | Premium or Standard tier only |
| Cut, polish, symmetry | Graded separately | Folded into the tier |
| Cut grade on fancy shapes | Yes, since September 2022 | Round brilliants only |
| Can verify a stated D–E / VVS floor | Yes | Not at grade level |
| Lab-grown market coverage | The large majority | Smaller share |
| Verification | Inscribed number + online lookup | Inscribed number + online lookup |
Does this make GIA the lesser laboratory?
No, and we will not pretend otherwise. GIA built the framework the entire industry uses, its mined-diamond grading remains the global benchmark, and it still grades mined diamonds on the complete 4Cs. Its rationale for the change — that a scale designed for a wide natural spread is a poor fit for a tightly clustered synthetic population — is a serious argument, not a retreat.
The distinction we are drawing is narrow and specific: for a lab-grown diamond being sold on a stated grade, a two-tier classification cannot do the verification job. That is a statement about what the document reports, not about the institution behind it. Anyone telling you GIA has become untrustworthy is overselling the story.
Does the laboratory cut-grade fancy shapes?
This difference predates the 2025 change and catches people out constantly. GIA assigns an overall cut grade only to round brilliants; on ovals, cushions, emeralds, pears and other fancy shapes, its reports state polish and symmetry but no overall cut grade. IGI has issued cut grades for fancy shapes since September 2022, assessing proportions and light return alongside the finishing grades.
The practical consequence: if a fancy-shape stone is offered to you as "Triple Excellent", that phrase requires three Excellent grades — and one of them may never have been issued. Since cut is the factor that most determines how a diamond actually looks, this is not a technicality. See why Triple Excellent matters and the proportions behind it in ideal cut, table and depth explained.
What to read on the certificate
- "Laboratory-grown" stated plainly. A legitimate report names the stone for what it is, and the girdle carries a matching inscription.
- Specific colour and clarity grades — not a tier — if you are buying on a stated specification.
- Cut, polish and symmetry as three separate lines. You want Excellent on all three. A stone can be advertised as "Excellent cut" while two of those lines sit lower.
- The measurements line. Millimetre dimensions reveal a stone cut deep to preserve weight, which wears smaller than its carat.
- The report number. Laser-inscribed on the girdle and verifiable on the laboratory's own website. Match the stone to the paper yourself.
Our full walkthrough is in how to read a diamond certificate.
The trap a certificate does not protect you from
A report grades the stone, not the price. A retailer can hand you an impeccable IGI certificate on a beautifully graded diamond and still mark the ring up several times over. The certificate tells you exactly what you are getting; it says nothing whatsoever about whether you are paying a fair price for it — a separate question, and often the more expensive one to get wrong. We run the actual arithmetic in what a lab-grown ring is really charging you for.
Why Montare specifies IGI
Our standard is stated as specific grades — lab-grown, D–E colour, VVS1–VVS2 clarity, Triple Excellent cut, ideal table and depth for the shape, three carats minimum. A floor written in specific grades is only meaningful if the report can confirm specific grades, so IGI certification is not a preference here; it is what makes the promise checkable.
You receive the report with the ring, the number inscribed on the stone, and a price that reflects the diamond rather than a century of retail markup. The full standard is on our standards page. If you are buying in Canada, our guide to buying lab-grown diamonds in Canada covers the local specifics — or build and price a ring directly in the ring builder.
Bring us any diamond you are considering — ours or someone else's — and we will read the certificate with you and show you exactly what the grades mean. No obligation.
Book a free consultation →Frequently asked questions
Is IGI or GIA better for a lab-grown diamond?
For a lab-grown diamond bought on a stated specification, IGI is the more useful report, because it still carries full D-to-Z colour and FL-to-I3 clarity grades. Since 1 October 2025 GIA issues only a two-tier Premium or Standard classification on lab-grown stones. Both laboratories are independent and rigorous; the difference is the resolution of what they report.
What changed with GIA lab-grown reports in 2025?
On 1 October 2025 GIA stopped issuing D-to-Z colour grades and specific clarity grades on laboratory-grown diamonds, replacing them with a Laboratory-Grown Diamond Quality Assessment carrying a two-tier Premium or Standard classification, an assessment number and a girdle inscription.
What is the difference between GIA Premium and Standard?
Premium covers D colour with VVS clarity or better, and Excellent polish and symmetry. Standard covers E through J colour with VS clarity, and Very Good polish and symmetry. Stones falling below the Standard thresholds receive no classification.
Does GIA still grade lab-grown diamond colour?
Not on the D-to-Z scale. A GIA lab-grown report issued from 1 October 2025 indicates only whether the stone meets the Premium or Standard tier, so it cannot distinguish a D from an E, or an E from a J within the Standard band.
Are IGI certificates trustworthy?
Yes. IGI is a long-established independent laboratory and grades the large majority of lab-grown diamonds. What matters is that the report is independent of the seller and that the laser-inscribed number on the diamond matches the certificate and verifies on IGI's own website.
Does a GIA report cut-grade fancy shapes?
No. GIA assigns an overall cut grade to round brilliants only; its fancy-shape reports carry polish and symmetry but no cut grade. IGI has cut-graded fancy shapes since September 2022, which matters if a stone is being described as Triple Excellent.
Do lab-grown diamonds come with a certificate?
A quality lab-grown diamond should always include an independent report stating "laboratory-grown" with a verifiable report number. If you are buying on a specific grade, check that the report actually states that grade rather than a tier. Every Montare diamond is IGI certified.
Does the certificate tell me if the price is fair?
No. A certificate grades the diamond, not the price. A genuine report can sit on a heavily marked-up ring, so judge the price against the stone's specifications and the market — not the paperwork alone.
Ready to see a certified stone at the standard? Build yours in the ring builder, or book a consultation with our Toronto team.
The Montare standard
Lab-grown · D–E colour · VVS clarity · Triple Excellent · 3ct minimum · IGI certified
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