TL;DR

A diamond certificate is a lab report that grades a stone's 4Cs — carat, colour, clarity, and cut. The two reports we trust most at Bijouterie Jamil in Montréal are GIA (Gemological Institute of America) for natural diamonds and IGI (International Gemological Institute) for lab-grown stones. AGS and HRD are also legitimate, but you'll see them less often in Canada. A certificate is not the same as an appraisal: the cert grades the stone, the appraisal sets a replacement value for insurance.

Table of Contents

1. What a diamond certificate actually is
2. The labs that matter: GIA, IGI, AGS, HRD
3. How to read a GIA or IGI report line by line
4. Certificate vs appraisal — they are not the same
5. What to do if your diamond has no paperwork
6. How we verify a stone in our Montréal shop
7. FAQ

What a Diamond Certificate Actually Is

A diamond certificate (sometimes called a grading report or lab report) is a document issued by an independent gemmological laboratory. The lab measures and grades the stone on the 4Cs and notes any treatments, fluorescence, and physical proportions. It also assigns a unique report number, which is often laser-inscribed on the diamond's girdle so the stone and the paper can be matched later.

The key word is independent. The lab does not own the diamond, does not sell it, and has no financial interest in the grade. That's why a GIA report from 2009 still holds weight in 2026 — the grading scale hasn't moved, and the lab has no incentive to inflate.

A certificate is not a guarantee of value. It is a guarantee of identity and quality. Two different jewellers can sell the same GIA-graded stone at very different prices. The cert tells you what you're buying. What you pay for it is a separate negotiation.

The Labs That Matter: GIA, IGI, AGS, HRD

Not every lab is created equal. Here are the four you'll actually run into in Canada, ranked roughly by how strict their grading is.

GIA — Gemological Institute of America

The gold standard for natural diamonds since 1953. GIA invented the 4Cs scale that the entire industry now uses. Their grading is consistent and conservative — a GIA "G colour, VS1 clarity" means the same thing today as it did twenty years ago. If you're spending more than $3,000 CAD on a natural diamond, we recommend it carry a GIA report. No exceptions.

IGI — International Gemological Institute

Founded 1975, headquartered in Antwerp. IGI is the dominant lab for lab-grown diamonds worldwide, and they're now the default for almost every lab-grown engagement ring sold in North America. For natural stones, IGI is also legitimate, but historically it has graded slightly looser than GIA — meaning an IGI "G/VS1" might grade as GIA "H/VS2". Not a scam, just a calibration difference. Worth knowing when you compare prices.

AGS — American Gem Society

AGS used a 0–10 numerical scale (0 = best) and was respected for cut grading in particular. In 2022, GIA acquired the AGS Laboratories operation, and AGS-style cut grading is now folded into GIA reports. You'll still see vintage AGS reports on older stones — they're trustworthy.

HRD — Hoge Raad voor Diamant

The Antwerp-based European lab. Common in European inventory, less common in Québec. HRD reports are credible but tend to grade slightly more liberally than GIA on colour. If a stone in our shop has only an HRD cert, we'll often re-verify it ourselves before quoting a price.

Labs we don't trust

EGL (European Gemological Laboratory) and its many regional offshoots — EGL USA, EGL Israel — have a long, well-documented reputation for over-grading. A diamond labelled "F/VS1" by EGL can come back two grades lower at GIA. We do not buy or sell EGL-graded stones at Bijouterie Jamil, and we recommend you avoid them too.

How to Read a GIA or IGI Report Line by Line

Open any GIA or IGI report and you'll see roughly the same fields. Here's what each one tells you, in order of how much it matters.

Report number. Usually 8–10 digits. This number is also (in most cases) laser-inscribed on the diamond's girdle in microscopic letters. Bring a 10x loupe and look — if the number on the stone matches the paper, you have the right stone.

Shape and cutting style. Round Brilliant, Princess, Oval, Emerald, etc. Sounds obvious, but make sure it matches what you see.

Measurements. In millimetres, always three numbers: length × width × depth. For a round brilliant, the first two should be nearly identical (e.g. 6.50 × 6.52 × 4.01 mm).

Carat weight. To two decimal places (e.g. 1.02 ct). One carat is 0.2 grams.

Colour grade. D (colourless) through Z (light yellow). D, E, F are colourless. G, H, I, J are near-colourless and where most buyers sit — it's where you stop paying for a difference your eye can't see.

Clarity grade. FL (flawless) through I3 (heavily included). VS1, VS2, SI1 are the sweet spot for value: tiny inclusions only a trained eye finds with magnification.

Cut grade. Excellent, Very Good, Good, Fair, Poor. This is the one most buyers underweight. Cut is what makes a diamond actually sparkle. A G/VS1 with a Poor cut will look duller than an H/SI1 with an Excellent cut. Don't compromise on cut.

Polish and Symmetry. Two more line items, both graded Excellent through Poor. Aim for Excellent or Very Good on both.

Fluorescence. None, Faint, Medium, Strong, Very Strong. Medium or strong blue fluorescence in a near-colourless stone is fine — sometimes it even helps the colour. Strong fluorescence in a D–F colour stone can cause a milky look in sunlight; that's the only case to avoid.

Comments and treatments. Any laser drilling, fracture filling, HPHT treatment, or "lab-grown" indicator will be noted here. Read this section carefully.

Plot diagram. A mapped sketch of the stone's inclusions. Useful if you ever need to prove identity later — your stone's inclusion fingerprint is unique.

Certificate vs Appraisal — They Are Not the Same

This is the single most common confusion we hear in our Montréal shop. A grading report (GIA, IGI) tells you what the stone is. An appraisal tells you what it would cost to replace. Different documents, different purposes.

Your insurance company will ask for an appraisal — not a GIA report — when you add a ring to a homeowner or tenant policy. The appraisal references the grading report, then assigns a Canadian dollar replacement value based on current market pricing in Québec. Most insurers want the appraisal updated every 3–5 years because gold and diamond prices move.

At Bijouterie Jamil we issue insurance appraisals on letterhead, signed and dated, with photos and full specs. Standard turnaround is 3–5 business days. We do this for pieces we sold and for pieces brought in from elsewhere — yes, we'll appraise a ring you bought somewhere else.

What to Do If Your Diamond Has No Paperwork

This happens constantly. Inherited rings, estate pieces, vintage stones from before lab grading was common — none of them come with a GIA report. That doesn't mean the stone is worthless or fake. It means you need to verify it the old-fashioned way.

You have three options:

1. Bring it to a local jeweller for in-shop verification. A trained gemmologist can confirm the stone is a real diamond (vs moissanite, CZ, or lab-grown) using a thermal/electrical tester, a loupe, and a microscope. Cost: usually free or $25–$50 CAD if a written opinion is needed. Takes 15–30 minutes.

2. Submit it to a lab for grading. We can ship a loose stone (or remove it from a setting first) to GIA or IGI for a full grading report. Cost: roughly $80–$300 CAD depending on carat weight, plus shipping and insurance. Turnaround: 3–6 weeks.

3. Get an appraisal without a lab cert. A qualified appraiser can issue an insurance appraisal based on in-house grading. The appraisal will note "graded in-house, no third-party report on file." Insurers in Québec accept this for pieces under roughly $10,000 CAD.

If you're not sure which route to take, walk into Bijouterie Jamil and we'll tell you straight. For a $1,200 ring you inherited from your grandmother, paying $250 to send it to GIA usually doesn't make sense. For a 2-carat stone in a Tiffany setting from the 1980s, it absolutely does.

How We Verify a Stone in Our Montréal Shop

When a customer brings us a diamond — to insure, to sell, to set, or just to verify — here's the actual process we run, in order:

1. Visual inspection under 10x loupe. Confirm shape, look for obvious treatments, inclusions, chips on the girdle.
2. Diamond tester. A combined thermal and electrical conductivity tester separates real diamond from moissanite, CZ, and synthetics in seconds.
3. Microscope at 40x. Map the inclusions, look for laser inscription on the girdle, verify the report number if a cert is present.
4. Measurement. Digital callipers and a calibrated scale. Length × width × depth in mm, weight in carats to 0.01.
5. Cross-reference the report. If a GIA or IGI cert came with the stone, we pull up the lab's online verification (gia.edu/report-check or igi.org) and confirm the report exists and matches what's in front of us. This catches forged certificates immediately.
6. Written opinion or appraisal. If you need it on paper, we issue it on Bijouterie Jamil letterhead within 3–5 business days.

The whole bench process for a single stone takes about 20 minutes. We don't charge for verification if you're already a customer or considering selling to us. For an independent insurance appraisal we charge $75–$150 CAD per piece depending on complexity.

If you're choosing between a lab-grown and a natural diamond, or working through our engagement ring buying guide, the certification step happens before you commit. Always.

FAQ

Do I really need a GIA certificate on my engagement ring diamond?

For natural diamonds above 0.50 ct or $3,000 CAD, yes. Below that threshold, an in-shop grading by a trusted local jeweller is usually sufficient. For lab-grown diamonds, look for an IGI report instead — that's the industry standard.

Is an IGI certificate as good as a GIA certificate?

For lab-grown diamonds, IGI is the standard and we trust it fully. For natural diamonds, GIA grades slightly stricter — an IGI "G/VS1" natural stone might come back from GIA as "H/VS2". Not dishonest, just calibrated differently. Adjust your price expectation accordingly.

What's the difference between a diamond certificate and a diamond appraisal?

A certificate (GIA, IGI) is a quality grading from an independent lab — it tells you what the stone is. An appraisal is a replacement value in Canadian dollars, usually for insurance. You typically need both: the cert lives with the stone for life, the appraisal gets refreshed every 3–5 years.

My diamond didn't come with any paperwork. Is it fake?

Not necessarily. Most estate, vintage, and inherited diamonds were never graded by a modern lab because grading wasn't widespread before the 1980s. Bring it to Bijouterie Jamil and we'll confirm authenticity in about 20 minutes using a diamond tester, microscope, and measurements. No charge for verification.

Can a diamond certificate be faked?

Yes, but it's easy to catch. Both GIA and IGI offer free online report verification — gia.edu/report-check and igi.org. Type in the report number from the paper and it should pull up an exact match of the stone's specs. Mismatch or "report not found" means the cert is forged or has been tampered with.

How much does it cost to get a diamond appraised in Montréal?

Standard insurance appraisal at Bijouterie Jamil runs $75–$150 CAD per piece. Complex pieces (multiple stones, antique settings) can run up to $200. Turnaround is 3–5 business days. We appraise pieces we sold and pieces from elsewhere.

Should I get my old appraisal updated?

Yes. Gold and diamond prices have moved significantly since 2020, and most insurers in Québec require updated appraisals every 3–5 years. An out-of-date appraisal can leave you under-insured if you ever lose or damage the piece.

What labs should I avoid?

We don't recommend EGL (European Gemological Laboratory) reports or any of its regional variants. They have a long history of over-grading colour and clarity by 1–3 grades compared to GIA. If you have a stone with only an EGL report and want a real grade, send it to GIA.

Get Your Diamond Verified in Montréal

If you have a diamond you want graded, appraised, or simply verified — bring it in. We're a family-run jewellery shop in Montréal, second generation, and we've been reading lab reports and grading stones for sixty years. Walk in, or book a 30-minute consultation and we'll give you a straight answer in plain French or English.

Book a verification appointment →

About the author Nader Khazzoum is a master jeweller at Bijouterie Jamil in Montréal, specialized in custom fabrication, stone setting, and laser welding. He has personally graded and set thousands of natural and lab-grown diamonds since joining the family business.