IGI vs GIA vs GRA vs GCAL: Grading Reports Compared

IGI vs GIA comes down to how each lab handles lab grown diamonds: IGI grades them with the full 4Cs (D to Z color, FL to I3 clarity), while GIA has placed them in "premium" or "standard" categories since October 1, 2025. GCAL is a smaller New York lab known for a light performance cut grade and a consumer guarantee. GRA is the report card that commonly comes with moissanite, and it is not comparable to an independent diamond lab report.

IGI vs GIA vs GCAL vs GRA at a Glance

The four names cover very different things, from the world's best-known diamond lab to a moissanite specification card.

Lab	Full name and background	Natural diamonds	Lab grown diamonds	Moissanite	How to verify
GIA	Gemological Institute of America; independent nonprofit established in 1931	Full 4Cs grading	"Premium" or "standard" quality assessment since October 1, 2025	Not graded on GIA diamond reports	GIA Report Check
IGI	International Gemological Institute; founded in Antwerp in 1975	Full 4Cs grading	Full 4Cs grading, same scale as natural	Not graded on IGI diamond reports	IGI Verify Your Report
GCAL	Gem Certification & Assurance Lab; New York, founded in 2001, majority owned by Sarine since 2023	4Cs plus optional 8X cut grade	4Cs plus optional 8X cut grade	Not mentioned in its services	GCAL certificate lookup
GRA	Card commonly shipped with moissanite; sources give different full names	No	No	Records moissanite specifications	Website or QR code printed on the card

GIA: Gemological Institute of America

GIA is an independent nonprofit, established in 1931, that created the D to Z color scale and the modern clarity scale used across the trade.

GIA introduced its diamond grading system in 1953, and its scales are the reference most other labs follow for natural diamonds. For lab grown diamonds, GIA changed course in 2025. It announced in June 2025 that it would stop using its natural-diamond color and clarity terms for man-made stones, and since October 1, 2025 its lab grown reports confirm the stone is laboratory grown and assign a "premium" or "standard" category based on combined color, clarity and finish metrics. Stones below its minimum receive no designation. GIA said more than 95% of lab grown diamonds entering the market fall into a narrow range of color and clarity. Lab grown reports issued before the change remain valid.

How to check a GIA report: enter the report number in GIA Report Check. According to a GIA alert published by the American Gem Society, every GIA diamond grading report issued since January 1, 2000 can be confirmed this way.

IGI: International Gemological Institute

IGI is a global grading lab founded in Antwerp in 1975, and it is the lab that grades most lab grown diamonds with full 4Cs reports.

IGI was founded by Marcel Lorié and today describes itself as operating 37 laboratories and 21 schools in 10 countries. Its shares have traded in India since December 2024. IGI began grading lab grown diamonds in 2005, and lab grown stones made up 54% of the diamonds it graded in its latest financial update reported by IDEX Online in July 2025. In its 2024 IPO prospectus, IGI estimated its share of global lab grown diamond certification at about 65%; that figure is company-reported.

In July 2025, after GIA's announcement, IGI confirmed it would keep applying the same 4Cs to both natural and lab grown diamonds "to prevent industry and consumer confusion." Like most labs, IGI states that its report is an opinion and not a guarantee, appraisal or warranty.

IGI vs GIA for Lab Grown Diamonds

For lab grown diamonds, IGI gives you a specific color and clarity grade, while a GIA lab grown report gives a broader quality category.

Feature	IGI lab grown report	GIA lab grown report (from October 1, 2025)
Color	D to Z letter grade	Folded into "premium" or "standard"
Clarity	FL to I3 grade	Folded into "premium" or "standard"
Confirms lab grown origin	Yes	Yes
Online verification	Report number or QR code	Report number

If you want to compare two lab grown stones grade by grade, an IGI report shows the exact grades. Grown Leo's loose lab grown diamonds are IGI certified, graded D to F color and VVS1 to VS2 clarity with Excellent cut. You can estimate how those grades affect cost with our lab grown diamond price calculator, and read more about grades in our 4Cs guide.

How to Check an IGI Certificate

Enter the report number from your IGI document on IGI's Verify Your Report page and confirm every detail matches.

Find the report number on the paper or digital report. Newer reports also carry a QR code.
Go to igi.org/verify-your-report, which accepts a report number, SKU or QR code scan.
Compare shape, measurements, carat weight, color, clarity and cut on screen with your document.
Ask a jeweler to read the laser inscription on the diamond's girdle with a loupe and confirm it matches the report number.

GCAL Certification: Gem Certification & Assurance Lab

GCAL is a New York lab, founded in 2001, that grades natural and lab grown diamonds and is known for its 8X cut grade and a money-back accuracy guarantee.

GCAL was founded by Don and Pamela Palmieri. In May 2023, Sarine Technologies completed the purchase of a 70% stake for about $5.7 million, and the lab now operates as "GCAL by Sarine." It opened a grading lab in Surat, India in 2024. GCAL's website lists ISO 17025 accreditation.

Two features set GCAL apart:

8X cut grade: introduced in 2021, it requires Excellent results in eight areas grouped as physical excellence (polish, symmetry, proportions), light performance (optical brilliance, fire, scintillation) and optical excellence (optical symmetry, hearts and arrows). GCAL says that fewer than 1% of round brilliants graded Excellent qualify as 8X, and it has added an oval version.
Consumer guarantee: GCAL's "Zero Tolerance" 4Cs consumer guarantee refunds consumers if the cut, color, clarity or carat weight stated on a certificate proves inaccurate, according to National Jeweler. GCAL describes its documents as guaranteed certificates.

How to check a GCAL certificate: enter the certificate number on GCAL's certificate lookup page. Lab grown certificate numbers carry an "LG" prefix.

What Is a GRA Certificate?

A GRA certificate is a card commonly supplied with moissanite that records the stone's specifications and a report number; it is not an independent lab grading report like those from GIA, IGI or GCAL.

A GRA card typically lists shape, measurements, carat weight, color, clarity and a report number that may also be laser inscribed on the stone. Sources do not agree on what GRA stands for. Sellers often use "Gemological Research Association," while a 2023 GIA alert published by the American Gem Society refers to "Gales Gemological Research Association (GRA)." One retailer reports that GRA describes itself as an organization dedicated to moissanite archiving and data recording, with no affiliation with GIA or any other gemological authority.

Points to know before relying on one:

It is a record, not an independent appraisal. Several moissanite retailers note that GRA is not an accredited lab and that an online lookup confirms the card number exists rather than that a gemologist examined your specific stone.
Counterfeits exist. In 2023, GIA warned that consumers had received jewelry they did not order, some with counterfeit GIA reports and some with GRA reports stating the stones were moissanite.
A test confirms the material. GIA notes moissanite is easily distinguished from diamond by a trained gemologist or reputable lab, and a jeweler's moissanite tester is a quick first check.

How to check a GRA report number: use the website or QR code printed on your card, enter the number exactly, and confirm the carat weight, color and clarity match. Then check that any girdle inscription matches the card. Our step-by-step guide on how to tell if a GRA moissanite report is fake covers this in more detail, and our VVS moissanite guide explains how moissanite clarity is described. You can also shop loose moissanite stones.

Which Report Should You Look For?

Match the report to the stone: GIA or IGI for natural diamonds, IGI or GCAL for full grades on lab grown diamonds, and a GRA card plus a tester result for moissanite.

Natural diamond: a GIA or IGI report with full 4Cs.
Lab grown diamond with exact grades: an IGI or GCAL report.
Lab grown diamond with GIA's assessment: a GIA report with a premium or standard category.
Moissanite: a GRA card as a specification record, with identity confirmed by a tester or gemologist.

Whatever the lab, verify the number online and check that the stone's inscription matches before you buy.

Frequently Asked Questions

Is IGI or GIA better for lab grown diamonds?

It depends on the detail you want. IGI grades lab grown diamonds with the full 4Cs, giving a specific color grade from D to Z and clarity grade from FL to I3. Since October 1, 2025, GIA places lab grown diamonds into "premium" or "standard" categories instead. If you want to compare stones grade by grade, an IGI report provides that information.

Does GIA still grade lab grown diamonds?

Yes, but differently. GIA still identifies and evaluates lab grown diamonds, but since October 1, 2025 its reports no longer use D to Z color or FL to I3 clarity grades for them. Each report confirms the stone is laboratory grown and assigns a "premium" or "standard" category based on color, clarity and finish metrics. Earlier GIA lab grown reports remain valid.

How do I check an IGI certificate?

Go to IGI's Verify Your Report page at igi.org and enter the report number printed on your document, or scan the QR code on newer reports. Compare the shape, measurements, carat weight, color, clarity and cut shown online with your paper report. A jeweler can also read the laser inscription on the girdle to confirm it matches the report number.

What is a GRA certificate for moissanite?

A GRA certificate is a card commonly shipped with moissanite that lists the stone's shape, measurements, carat weight, color, clarity and a report number. It is not an independent lab grading report like those from GIA or IGI, and sources disagree on GRA's full name. Treat it as a specification record and confirm the stone with a moissanite tester or gemologist.

What is GCAL certification?

GCAL, the Gem Certification & Assurance Lab, is a New York grading lab founded in 2001 and majority owned by Sarine Technologies since 2023. It grades natural and lab grown diamonds, offers an 8X cut grade that includes light performance measures such as brilliance, fire and scintillation, and backs its certificates with a consumer guarantee on the stated 4Cs.

Can a GRA report be fake?

Yes. In 2023, GIA warned that consumers were receiving unsolicited jewelry with counterfeit reports, including some GRA reports stating the stones were moissanite. Check the number on the website or QR code printed on the card, make sure the carat weight and grades match, confirm the girdle inscription matches, and have the stone tested to confirm it is moissanite.

Sources

Previous post Diamond Color Chart: The D to Z Scale Explained

IGI vs GIA vs GRA vs GCAL: Diamond and Moissanite Reports Compared