IGI Certified Diamond: Is It as Good as GIA in 2026?
By SGJ · · 9 min read
An IGI certified diamond is a stone graded by a commercially owned laboratory. A GIA one is graded by a non-profit. That is the real difference behind the question everybody actually asks, and almost nobody writing about it says so out loud.
It matters less than it sounds. But you cannot judge a certificate without knowing who wrote it, so start there.
What IGI is
The International Gemological Institute opened in Antwerp in 1975 and now runs laboratories in ten countries, including grading labs in Mumbai and Surat. It grades natural diamonds, laboratory-grown diamonds, coloured stones and finished jewellery, on the same four-C scales the trade has used for decades.
The ownership is the part worth knowing. In May 2023 IGI was bought by Blackstone, the private equity firm, from the founding Lorie family and Fosun's Shanghai Yuyuan. GIA, by contrast, has been a non-profit since 1931.
Does that make IGI less trustworthy?
Not in the way the framing suggests. A grading report is not worth anything because of the lab's tax status; it is worth something because a third party wrote it down and publishes a database you can check it against, without asking the seller's permission. IGI publishes one. So does GIA. So does HRD.
It is also worth knowing that GIA's laboratory arm has been a substantial revenue business inside the non-profit for years. The clean line between charitable institute and commercial lab is blurrier than the labels imply, in both directions.
Where ownership does bite is on incentives — a lab that grades for a fee has a customer, and the customer submits the stones. That argument applies to every commercial laboratory in the trade, and the defence against it is the same everywhere: the grades are published, the database is public, and a lab that drifts gets found out by the next lab that regrades the stone.
Does an IGI certified diamond get an easier grade?
You will read constantly that IGI grades more generously than GIA. The published evidence does not support it, which is worth saying because almost nobody does.
The comparisons that exist are small, and they do not point where the rumour points. A retrospective of twenty-nine dual-certified stones found IGI's colour grading stricter than GIA's more often than looser — twelve stricter, seven the other way, ten identical — with clarity matching on twenty of the twenty-nine. Rapaport's own grading survey placed IGI second of the six laboratories it tested. IGI has published a direct rebuttal since 2020. And GIA has never made the accusation: it argued its October 2025 decision on entirely different ground, that lab grown stones now cluster in too narrow a band for the old scale to say anything useful.
So treat "IGI grades soft" as trade folklore until somebody publishes a blind study. The narrower truth underneath it still matters: two laboratories reading the same stone can land a step apart, in either direction. A step is invisible on a hand — the clarity ladder shows where that line falls — and very visible on a price.
Which produces the only rule that protects you here: compare quotes graded by the same laboratory, or do not compare them. A quote on IGI paper against one on GIA paper is two different measurements, and the gap between them is not a saving.
Which report you are holding
IGI does not issue one document. It issues several, and buyers routinely mistake one for another.
- A diamond report — what people mean by an IGI certified diamond — covers one loose stone: shape, measurements, carat, colour, clarity, cut where it is graded, polish, symmetry, fluorescence, and whether the stone is laboratory-grown or natural.
- A jewellery report covers a finished piece. It describes the setting and the stones in it, and it is not a grading report for any single stone.
- On many lab grown reports, IGI also states the growth method — CVD or HPHT — which is worth knowing if you have a view on the two.
That distinction matters most when you are buying something already made. A pair of studs sold with "IGI certified" on the tag might carry two stone reports, or one jewellery report, and those are not the same promise. Ask which.
What changed at the labs in 2025 and 2026
Two events, and between them they reshaped which paper a lab grown stone can even get.
GIA stopped putting four-C grades on white lab grown diamonds in October 2025, replacing them with a Premium or Standard classification — and a stone that misses any of its minimums — VS clarity, J colour, Very Good polish and symmetry — gets no assessment at all, which is why an ordinary SI stone now has nowhere to go at GIA. Then in 2026 HRD left loose lab grown certification altogether.
So of the three laboratories an Indian buyer is usually offered, only IGI still puts colour and clarity grades on a loose white lab grown stone. Two qualifiers matter. GIA still writes full reports, clarity plot included, on lab grown coloured stones. And smaller laboratories do still grade the four Cs on lab grown — GCAL, GSI, and Mumbai's own SGL among them — so "IGI or nothing" is only true of the big three. If you want the mechanics of the GIA change and what its lookup now returns, that is its own guide.
What an IGI certified diamond gets you, and what it does not
Not a scoreboard. Two documents built for different jobs.
| On a white lab grown stone | IGI | GIA |
|---|---|---|
| Colour, clarity, cut | Graded separately on the letter scales, with a cut grade on nine shapes | One word standing in for five inputs: clarity, colour, polish, symmetry, cut |
| Measurements | Printed | Dropped from the assessment |
| A stone missing any minimum | Graded normally | No assessment, and a fee anyway |
| Growth method | Stated, CVD or HPHT | Not distinguished |
And where GIA is the stronger document: on lab grown coloured stones it still issues a full report with a plotted clarity diagram, and on natural stones it remains the older name and the one the trade pays a premium for.
One thing worth being precise about, because most write-ups get it wrong: GIA's lab grown assessment carries no cut grade at all. Cut is folded into the single descriptor with everything else. GIA does add fancy-shape cut grades in 2027 — marquise, oval and pear — though it has not said whether that extends to lab grown stones.
The nine IGI grades for cut are princess, oval, pear, marquise, heart, emerald, square emerald, square cushion and cut-cornered square. Note what that list leaves out: the elongated versions. A rectangular cushion or a stretched radiant gets no cut grade from either laboratory.
When we tell people not to pay for a certificate
Small stones. If a ring carries a centre stone and a halo of melee, the melee is not individually certified anywhere in the trade, and it should not be — a per-stone report on a two-point diamond costs more than the diamond. Anyone offering to certify every stone in a pavé band is selling you paperwork.
The same goes for a stone already set. Loose-stone reports are for loose stones; once it is in a mount, no laboratory is regrading it without the setter taking it out first, and that is a cost with no buyer.
Certification earns its money on the centre stone. Ask for it there, and do not let anybody sell you more of it than that.
What to ask for
- Name the laboratory before you talk price. For a loose white lab grown stone in 2026, ask for IGI. For a natural stone, IGI, GIA and HRD are all real answers.
- Ask for the report number, not a photo of the report. The number is what the database answers to, and checking it takes a minute.
- Check the report type, not for a word. A lab grown stone's report says so on its face. A natural stone's report is simply a different document — it does not usually carry a line declaring the stone natural, so do not go hunting for one. If nothing on the paper names an origin either way, that is your question.
- On a fancy shape, find out whether cut was graded. If it was, that is the most useful line on the page. If not, you are judging proportion from millimetres.
- Get a second quote on identical paper. Same laboratory, same grades, same weight.
The questions buyers actually ask
Is IGI certification reliable?
Yes. IGI grades to the same four-C scales as the other major laboratories and publishes a database anybody can check a report number against. Reliability and strictness are separate questions — a laboratory can be entirely reliable and still grade half a step differently from its neighbour.
Is an IGI certified diamond worth less than a GIA one?
On a natural stone the trade does pay a premium for GIA paper, which is a market preference rather than a statement about the stone. On a lab grown stone the comparison has largely stopped being possible, because GIA no longer issues the grades you would be comparing.
What is printed on an IGI diamond cert?
Shape, measurements, carat weight, colour, clarity, cut where graded, polish, symmetry, fluorescence, the report number, and whether the stone is laboratory-grown or natural. Lab grown reports often add the growth method, and there is usually a plotted diagram of the inclusions.
Does IGI grade natural diamonds too?
Yes, and always has. IGI is best known for lab grown work because it built grading parameters for those stones early, but natural stones go on the same scales. The laboratory is not the origin.
Ask which paper, then go and check it
The useful thing about all three of these laboratories is the same thing: they publish, so you do not have to believe anybody, including us.
Message us on WhatsApp about a piece you are weighing up. For any certified piece we quote, you get the laboratory's name and the report number, and you look it up yourself before deciding anything. That is what the number is for.
Both lines come off the same Mumbai bench, and we hold Bharat Diamond Bourse and GJEPC membership. We deliver across India; the showroom runs by appointment. Talk to us when you are ready, or see what a finished piece looks like in lab grown diamond rings and diamond earrings. Everything else we have written sits on the guides index.