How to Read an IGI Certificate and Compare Diamond Prices
The single most important document in the lab diamond market, explained field by field, plus how to verify it free and use it to spot fair pricing.
The author is the founder of Draco Diamond. Every IGI report referenced is verifiable free on the IGI public database at IGI.org. All prices in CAD.
Understanding the certificate layout
IGI, the International Gemological Institute, issues certificates in a standardized layout with fields in consistent locations. The report number sits at the top right, the grading results in the center, and the proportions diagram on the right. Once you know where each field lives, any IGI report reads the same way.
Top to bottom, an IGI report contains:
| Field | What it tells you |
|---|---|
| Report number | Unique identifier, top right (format LG123456789) |
| Date of issue | When graded, indicates the grading standards version |
| Shape and cut | Round brilliant, oval, cushion, and so on |
| Measurements | Length by width by depth in millimeters, two decimals |
| Carat weight | Total weight to two decimal places |
| Color grade | D to Z scale; lab diamonds typically D to F |
| Clarity grade | FL, IF, VVS1, VVS2, VS1, VS2, SI1, SI2 |
| Cut grade | Excellent to Poor (round diamonds only) |
| Polish and symmetry | Surface finish and facet alignment |
| Comments | Notes, typically "Laboratory Grown" |
"A certificate confirms the diamond. Marketing language confirms nothing. Read the report before the price tag."
Garrett McMartin, Founder, Draco Diamond
The four fields that determine 90 percent of value
Four fields decide most of what a diamond is worth, and each must match the seller's listing exactly. Understanding what the grades mean prevents paying for terminology.
What determines a diamond's value
Four grades account for roughly 90 percent of price. Everything else on the report is secondary.
Illustrative weighting based on the IGI 4Cs valuation framework.
Carat weight is the headline number but the most overpaid for; a 1.90ct and a 2.00ct look nearly identical on the hand at very different prices. Color on the D to Z scale matters most in the colorless D to F band, where Draco grades every stone. Clarity from VS2 up is eye clean, so paying for VVS or IF buys a distinction invisible without magnification. Cut, on round diamonds, is the one grade never to compromise, because it governs how much light the stone returns.
How to verify a report at IGI.org
Verification is free, public, and takes under three minutes. It is the single check that separates a real certified diamond from a claim.
Locate the report number at the top right of the certificate. Lab grown reports use the format LG followed by a string of digits.
Go to IGI.org and use the Verify Your Report tool. Enter the report number. The official certificate should load with full grading details.
Confirm carat weight, measurements, color, clarity, and cut on the IGI database match the seller's listing exactly. Any mismatch is a reason to stop and ask questions.
Comparing certificates between sellers
Once two diamonds carry matching IGI specifications, the only remaining variable is price. Identical grades at different prices reveal where retail markup sits. Here is the same 1.0 carat round brilliant, certified to the same grades, priced by two sellers:
| Specification | Seller A | Seller B |
|---|---|---|
| Carat | 1.00 | 1.00 |
| Color | F | F |
| Clarity | VS2 | VS2 |
| Cut | Excellent | Excellent |
| Certification | IGI | IGI |
| Price | higher | up to 40–60% less |
When the certificates match field for field, you are comparing the same product. The difference in price is the retail structure, not the diamond. Direct to consumer brands routinely price 40 to 60 percent below multi tier retailers for identical IGI grades.
Red flags in a certificate
A few warning signs justify pausing a purchase until they are explained:
If the number does not load on IGI.org, the certificate cannot be confirmed. A diamond that cannot be verified is a diamond to walk away from.
If the millimeter measurements on the listing differ from the IGI report, the stone shown may not be the stone certified.
"Certified" means nothing without a recognized lab (IGI, GIA, or GCAL). In-house or unnamed certificates are not independent.
Certificate vs marketing claims
Marketing language is designed to sound like a grade without being one. The report is the translation:
| Marketing claim | Certificate reality |
|---|---|
| "Premium quality" | No defined grade. Check the actual clarity and color. |
| "Near colorless" | Usually G to J. Confirm the exact letter grade. |
| "Eye clean" | Typically VS2 or better, but verify the clarity grade. |
| "Excellent sparkle" | Only meaningful if cut grade is Excellent on a round. |
| "Certified diamond" | Confirm the lab: IGI, GIA, or GCAL. |
Every Draco diamond is IGI certified, E to F color, VS2+ clarity, and ships with its certificate. The report can be provided on request before purchase and verified free at IGI.org. The grade is the promise, not the adjective. For the carat by carat economics behind these grades, see the lab grown diamond price per carat analysis.
IGI certificate FAQ
How do I verify the quality of a lab grown diamond before buying?
Confirm it is IGI certified, then read the four grades that set quality: cut, color, clarity, and carat. Look for cut Excellent or better, color in the E to F range, and clarity VS2 or higher, the point where inclusions are not visible to the eye. The IGI report number is verifiable free at IGI.org, and the full certificate is included with every Draco order. To confirm a specific stone first, the report is available on request.
Is IGI certification as good as GIA?
For lab grown diamonds, IGI is the leading global standard and grades the majority of lab grown stones worldwide, using the same 4Cs criteria. GIA also grades lab grown diamonds. Both are independent and verifiable; IGI is the more common lab grown report and is fully accepted across the market.
How do I verify an IGI report is real?
Go to IGI.org, open the Verify Your Report tool, and enter the report number from the certificate. The official report loads with full grading details. Match every field to the seller's listing. Verification is free and takes under three minutes.
What do the grades on an IGI lab diamond report mean?
Color runs D (colorless) to Z; lab diamonds typically grade D to F. Clarity runs FL down through SI2; VS2 and above is eye clean. Cut, on round diamonds, runs Excellent to Poor and governs light return. Carat is total weight to two decimal places.
Do all lab grown diamonds come with an IGI certificate?
Reputable lab grown diamonds do. Every Draco diamond is IGI certified, E to F color, VS2+ clarity, with the report number verifiable at IGI.org. A stone sold without independent certification cannot be verified and should be treated with caution.
Can an IGI certificate be faked?
A printed certificate can be altered, which is exactly why you verify the report number directly on IGI.org rather than trusting the document alone. If the number does not load on the official database, or the loaded details do not match the listing, do not proceed.
References
- International Gemological Institute. Verify Your Report and grading standards. IGI.org.
- Draco Diamond published catalog and grading standard, dracodiamond.com. Accessed June 2026.
IGI certified across the entire catalog
Every Draco diamond is IGI certified, E to F color, VS2+ clarity, and the certificate is included with every order. Priced direct, up to 64 percent below legacy retail, with free insured worldwide shipping and 30 day returns.
