When you're spending thousands of dollars on a diamond engagement ring, you want to know exactly what you're getting. That's what diamond certification is for — and IGI certification in particular has become the gold standard for lab grown diamonds.
If you've been shopping for engagement rings and noticed that some diamonds come with IGI certificates and others don't, this guide explains what that certificate actually tells you, why it matters, how IGI compares to GIA, and why you should never buy a diamond — lab grown or mined — without one.
What Is IGI?
IGI stands for the International Gemological Institute. Founded in Antwerp, Belgium in 1975, IGI is one of the world's largest and most respected independent diamond grading laboratories. It operates grading facilities in major diamond trading centers including Antwerp, New York, Mumbai, Dubai, Hong Kong, Tokyo, Bangkok, and Los Angeles.
IGI is an independent third party — meaning it has no financial stake in the sale of any diamond it grades. Its only job is to examine diamonds and report their characteristics accurately. That independence is what makes its certificates meaningful.
Over the past decade, IGI has become the leading certification body for lab grown diamonds specifically. As the lab grown diamond market has grown, IGI has invested significantly in the expertise and technology required to grade lab grown stones with the same rigor applied to mined diamonds.
What Does an IGI Certificate Tell You?
An IGI diamond grading report is a detailed document that records every measurable characteristic of a specific diamond. Each certificate is tied to a unique report number that can be verified on IGI's website — so you can confirm the certificate is genuine and matches the stone you're buying.
Here's what an IGI certificate covers:
The 4 Cs
- Cut grade: How well the diamond was cut and proportioned to maximize light performance. Grades range from Excellent to Poor. Cut is the most important factor in how brilliant and beautiful a diamond looks.
- Color grade: The degree of colorlessness, graded on a scale from D (perfectly colorless) to Z (visibly yellow or brown). Most engagement ring buyers target D–H grades.
- Clarity grade: The presence, nature, size, and location of any internal inclusions or surface blemishes. Grades range from Flawless (FL) to Included (I3).
- Carat weight: The precise weight of the diamond, measured to the nearest hundredth of a carat.
Shape and Cutting Style
The certificate identifies the shape (round, oval, cushion, princess, etc.) and the cutting style (brilliant, step cut, mixed cut).
Measurements
The exact dimensions of the diamond in millimeters — useful for confirming the stone fits the setting correctly and for comparing apparent size across different shapes.
Polish and Symmetry
Separate grades for how smoothly the facets were polished and how precisely they are aligned and shaped. Both are graded from Excellent to Poor and contribute to overall light performance.
Fluorescence
Whether the diamond exhibits fluorescence under UV light, and how strong that fluorescence is. This can subtly affect appearance in certain lighting conditions.
Proportions Diagram
A visual diagram showing the diamond's exact proportions — table percentage, depth percentage, crown angle, and pavilion angle. These measurements are what determine whether a diamond is cut to ideal proportions for maximum brilliance.
Clarity Plot
For stones with inclusions, a map showing the exact location and nature of each inclusion. This is useful for identifying the specific stone and understanding what, if anything, is visible inside it.
Origin Identification
For lab grown diamonds, the IGI certificate explicitly states "Laboratory Grown" as the origin. This is an important disclosure that distinguishes the stone from mined diamonds on the official record.
Why Does Certification Matter So Much?
Without a certificate from an independent laboratory, you are relying entirely on the seller's description of the diamond. The seller has a financial interest in presenting the stone favorably. An independent certificate has no such interest — it just reports what the stone is.
Consider what's at stake. Two diamonds can look nearly identical to the naked eye but have very different quality grades — and very different prices. A diamond described as "G color, VS2 clarity" by an uncertified seller might actually be J color and SI2 clarity. That difference could represent thousands of dollars and a significant gap in quality.
A certificate from IGI or GIA gives you:
- Verification that the diamond is what the seller says it is
- Documentation of the stone's exact characteristics, permanently on record
- Assurance from a party with no financial stake in the sale
- Protection if you ever need to insure, appraise, or sell the stone
- Confidence that you're making an informed purchase
This is why every lab grown diamond engagement ring at Anjays Designs comes with an IGI certificate. You should know exactly what you're buying — and you should be able to verify it independently.
Browse our IGI-certified lab grown diamond rings →
IGI vs. GIA: What's the Difference?
GIA — the Gemological Institute of America — is the other major diamond grading laboratory you'll encounter when shopping. Both are respected independent organizations, but they have different strengths and histories in the lab grown diamond space.
| Factor | IGI | GIA |
|---|---|---|
| Founded | 1975, Antwerp | 1931, USA |
| Reputation | Excellent — leading lab grown certifier | Excellent — historic leader for mined diamonds |
| Lab grown diamond grading | Extensive, industry-leading | Available, growing |
| Market share for lab grown | Dominant | Smaller but respected |
| Certificate cost | Lower | Higher |
| Grading consistency | Excellent | Excellent |
| Verification | Online via report number | Online via report number |
For lab grown diamonds specifically, IGI is the industry standard. The majority of reputable lab grown diamond jewelers use IGI certification because IGI has invested more deeply in the technology and expertise required to grade lab grown stones accurately and consistently. GIA certification is equally credible when you encounter it — both are trustworthy — but IGI is simply more prevalent in the lab grown market.
For mined diamonds, GIA has historically been considered the most conservative and consistent grader, and a GIA certificate often carries a slight premium. But for lab grown diamonds, IGI is the benchmark.
What About Other Certifications?
You may encounter diamonds certified by other laboratories — EGL, AGS, SGL, and others. Here's an honest guide to what those mean:
- AGS (American Gem Society): Respected, independent, known for rigorous cut grading. Trustworthy but less common for lab grown diamonds.
- EGL (European Gemological Laboratory): Historically known for inconsistent grading standards — some EGL grades are considered more lenient than IGI or GIA for the same stone. Approach with caution.
- SGL and other lesser-known labs: Without a strong reputation for independent, consistent grading, certificates from smaller or less established labs offer less assurance. Treat them as the seller's word, not independent verification.
- No certificate: Never buy a significant diamond without a certificate from IGI or GIA. No exceptions.
How to Verify an IGI Certificate
Every IGI certificate has a unique report number printed on the document. You can verify any IGI certificate by visiting igionline.com and entering the report number. The official record will show you the grading details for that specific diamond.
When you buy an IGI-certified diamond from Anjays Designs, we encourage you to verify the certificate yourself. The report number on the physical certificate should match the record on IGI's website, and the characteristics listed should match the stone in your ring.
This verification step takes about two minutes and gives you complete confidence that what you purchased is exactly what was represented.
Does the Certificate Affect the Price?
Yes, in two ways. First, the cost of certification itself is factored into the price — IGI charges a fee to grade and certify each stone, and that cost is passed along. This is a worthwhile cost: you're paying for independent verification of a significant purchase.
Second, certified diamonds tend to sell at slightly higher prices than uncertified stones of nominally similar quality, because buyers (correctly) trust them more. An uncertified diamond described as "1ct, G, VS2" cannot be independently verified — a certified diamond with the same specs has that verification on record.
The premium for certification is well worth it. Buying an uncertified diamond to save a small amount is a false economy — you're trading documented quality for an unverifiable claim.
What Happens to the Certificate After Purchase?
Keep it. The IGI certificate is a permanent record of your diamond's characteristics and should be stored safely alongside other important documents. It serves several purposes after purchase:
- Insurance: Jewelry insurers typically require a grading certificate or independent appraisal to insure a diamond ring. Your IGI certificate documents what the stone is, which forms the basis of the insured value.
- Appraisal: If you get a jewelry appraisal for insurance purposes, the appraiser will reference the grading certificate to verify the stone's characteristics.
- Resale or upgrade: If you ever sell or trade in the diamond, the certificate provides documentation that supports the stone's stated quality.
- Peace of mind: If the ring is ever repaired, resized, or serviced, you can verify afterward that the original stone was returned by cross-referencing the certificate's characteristics.
Frequently Asked Questions About IGI Certification
Is an IGI certificate the same as an appraisal?
No — these are two different documents that serve different purposes. An IGI certificate is a grading report that documents the physical characteristics of the diamond (cut, color, clarity, carat). It does not assign a dollar value. A jewelry appraisal, conducted by a certified appraiser, assigns a monetary value to the ring based on current market conditions. You typically need both — the certificate to document what you have, and an appraisal to establish insured value. Some insurance policies accept the purchase receipt plus the grading certificate; others require a separate appraisal.
Can I trust an IGI certificate from any jeweler?
Yes — the certificate is issued by IGI independently, not by the jeweler. A jeweler cannot alter or influence an IGI grading report. You can verify any IGI certificate directly on IGI's website using the report number, regardless of which jeweler sold the ring. The certificate is always between you and IGI, not between you and the seller.
What if my diamond doesn't come with a certificate?
For any significant diamond purchase — anything over a few hundred dollars — we strongly recommend insisting on an IGI or GIA certificate. If a jeweler cannot provide one, either the diamond has not been certified (a red flag for quality assurance) or the jeweler is unwilling to have it verified (a larger red flag). Walk away and find a jeweler who provides full certification.
Does IGI certify both mined and lab grown diamonds?
Yes. IGI grades both natural mined diamonds and lab grown diamonds using the same 4 Cs standards. The certificate clearly identifies the origin — "Natural" or "Laboratory Grown" — as part of the grading report. The grading standards themselves are the same for both types.
How long is an IGI certificate valid?
IGI certificates do not expire. A diamond's physical characteristics do not change over time, so the grading report remains accurate and valid indefinitely. The report number can always be verified on IGI's website regardless of when the certificate was issued.
What is the IGI report number and where do I find it?
The report number is a unique identifier printed on the front of every IGI certificate. It's also sometimes laser-inscribed on the diamond's girdle (the thin edge around the widest part of the stone) — visible under 10x magnification. You can enter this number at igionline.com to pull up the full grading record for that specific stone.
Shop With Confidence at Anjays Designs
Every lab grown diamond ring at Anjays Designs comes with an IGI certificate — no exceptions. We believe you should know exactly what you're buying, and we stand behind every stone we sell with full independent documentation.
Our collection includes handmade rings in solid 14K and 18K gold, set with IGI-certified lab grown diamonds graded to the specifications listed on every product page. When you buy from us, the grades are real, the certificate is genuine, and the stone in your ring is exactly what we say it is.
Ready to find your ring?
Have questions about a specific stone's certificate or grading? Contact us — we're happy to walk you through it.