​IGI vs GIA | What is the Difference?

​IGI vs GIA | What is the Difference?

​IGI vs GIA | What is the Difference?

Posted by Sharif Khan on 11th Feb 2022

Comparing IGI to GIA

IGI is Improving, but is still not on par with GIA!

The Gemological Institute of America (GIA) is one of the best grading labs in the world. It is often consistent in grading diamonds, and a standard-bearer for diamond certification and grading in the diamond industry.

The International Gemological Institute or IGI is also a very large institution, and it has been around since 1975.

While both GIA and IGI are reputable labs, there are noticeable differences in how they grade diamonds.

In a nutshell, IGI is not as consistent or strict in grading diamonds as GIA. While considering an IGI graded diamond, read our tips below carefully to avoid making obvious mistakes and know exactly what you are in for when buying such diamonds.

The reports issued by IGI for lab-grown diamonds are stricter and more accurate compared to their reports for natural mined diamonds. 

James Allen

GIA and IGI: Who are they?

What is GIA?

The Gemological Institution of America was founded in 1931 as a non-profit institution dedicated to the research, education, and grading of natural gemstones.

GIA wanted to develop a standard so that everyone in the industry was able to use one unified and standard methodology for grading diamonds and other gemstones.

As a result of their dedication and hard work, GIA introduced the International Diamond Grading System (known as the 4Cs – cut, clarity color, and carat weight) in 1953. Today, this system is used by everyone, including IGI.

GIA also trains gemologists and has 11 campuses. Moreover, they have 9 laboratories and 4 research centers and operate in 13 countries.

Check out GIA certified diamonds at James Allen.

What is IGI?

The International Gemological Institute is the largest independent gem lab in the world. It is headquartered in the heart of the diamond trade, Antwerp (where De Beers also has major operations). The company also has offices in several diamond centers around the world such as New York, New Delhi, Surat, Hong Kong, Dubai, Shanghai, and Tel Aviv, among others.

With over 650 gemologists and other jewelry professionals, IGI has been increasingly trying to position itself as a reliable diamond grading laboratory in order to establish a name for itself in the diamond industry.

Check out IGI graded diamonds at Brilliant Earth.

What is the main difference between IGI and GIA?

In Europe and Asia, IGI's grading reports are very common. However, in recent years, GIA is gaining more market shares there. In the United States, GIA is by far the first go-to lab.

In our opinion, IGI is not as strict as GIA when grading diamonds, but it does not mean that a buyer should entirely rule them out. As explained below, as long as they make an informed decision, buyers will still get a decent diamond for their money.

Blue Nile

Here is what to expect. The Difference between IGI and GIA in grading the 4Cs:

Because IGI is loosely structured globally, there can be slight inconsistency between the different IGI labs depending on their location.

As a role of thumb, it is safe to assume a 1-grade color inconsistency in D to I color diamonds between GIA and IGI graded diamonds. This inconsistency is much smaller J and lower color range diamonds.

It is also safe to assume a 1-grade clarity inconsistency in IGI and GIA graded diamonds, especially in high investment-grade diamonds in the D-F color and Flawless to VVS clarity range.

Be very clear with the retailer and ask questions about the clarity of SI1 and SI2 IGI graded diamonds as they might not be eye-clean. Make sure that low clarity grade IGI diamonds are eye-clean with no obvious noticeable inclusions.

On the bright side, around 10-20% IGI graded diamonds might end up being consistent with how GIA would grade them. How? Because diamonds are graded by human beings; individual gemologists, and then cross-examined. Therefore, some gemologists in IGI may be as strict as those in GIA. The problem is that they do not have the same consistency in grading diamonds across the organization as GIA does.

The moral of the story is that unless it is a very good deal, you are most probably not getting a good price on an IGI graded diamond --- it is just graded higher than it would in a GIA report.

Think about it, every dealer knows that they would get a better price for a GIA graded diamond (if it is a high-quality stone as the report says it is) and that the stone would also sell fast. So what is their incentive to grade the diamond by IGI? Deep down they know that IGI is more lenient than GIA and would give more favorable results.

Types of reports to look for while buying IGI and GIA graded diamonds:

GIA has diamond dossiers (generally for small diamonds) and full grading reports for any size diamond. IGI also has two types of diamond grading reports, mini-reports, and full grading reports.

Unlike the GIA dossiers that have sufficient information on them, IGI’s mini grading reports often issued to vendors in shopping malls are notoriously limited in how much information they provide, especially about the cut of a diamond.

If you are buying an IGI graded diamond, make sure you buy a diamond that comes with a full IGI report issued by one of their well-established labs in the U.S. or Antwerp.

GIA Certified Diamonds


While IGI is a reliable lab, it is still not as strong as GIA. However, there is no reason to entirely rule out IGI. Just work with an assumption that when it comes to diamond clarity and color, there might be slight inconsistency between IGI and GIA.

When buying IGI graded diamonds, buy ones with a full IGI report, not the mini-reports as they do not have any cut information on them. Moreover, buying an IGI diamond with lab reports from their more established labs in the U.S. and Europe might be a good idea. It is also important to note that IGI is not as inconsistent in low-grade diamonds as they are in high-grade diamonds.

Our best advice would be to go for a GIA certified diamond and avoid taking the risk altogether if you are a first-time buyer.

As you shop for a perfect diamond, we would also suggest that familiarize yourself with the seven factors that affect the price of a diamond as well as with the four scenarios that buyers consider while shopping for a diamond.

The seven factors include diamond shape, carat weight, color, cut, clarity, fluorescence, and certification (a topic we just discussed here).

Finally, here is a list of our top websites for buying diamonds or engagement rings online

Example of a full IGI Grading Report:IGI Diamond Certificate

Example of a Mini IGI Report

Small IGI Certificate