​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 18th May 2019

IGI is improving, but is still not on par with GIA...

The Gemological Institute of America or GIA is the best lab in the world. It is very consistent, and a standard bearer for  diamond certification in the 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 is noticeable difference in how they grade diamonds.

In a nutshell, IGI is not as consistent or strict in grading diamonds as GIA. However, if you are considering an IGI graded diamond, read our tips below carefully so you know exactly what you are in for in order to make an informed decision while buying  loose diamonds as well as to avoid making certain mistakes.

James Allen

First, let’s learn about GIA and IGI in detail...

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 method 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 a standard that is used by everyone, including IGI.

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

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, Honk Kong, Dubai, Shanghai, and Tel Aviv, and 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 GIA Certified Diamonds at James Allen.

So what is the difference between IGI and GIA?

If you travel abroad in Europe and Asia, IGI grading reports are very common; however, in recent years, GIA is gaining more market shares there as well. In the U.S., GIA is by far the first go to lab.

In our opinion, IGI is not as strict as GIA when grading diamonds. It doesn't mean though that you should entirely rule out IGI. Just know what to expect and you will be fine.

Blue Nile

Here is what you should expect. The Difference between IGI and GIA in grading the 4Cs…

Because IGI is loosely structured worldwide, 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. We wouldn’t worry too much between the difference of IGI and GIA graded diamonds in 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 dealer and ask questions about the clarity of SI1 and SI2 graded IGI diamonds as they might not be eye-clean. Make sure you verify with them that such low clarity grade IGI graded diamonds are eye-clean (if you after eye clean diamonds).

On the bright side, around 10-20% (our guesstimation) 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, it is possible for some gemologist in IGI to 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 morale of the story is that unless it is a very good deal, you are most probably not getting a good deal 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 would be more lenient with them than GIA and that they might get more favorable results.

Types of reports for look for while buying IGI 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, the small reports and full grading reports.

Unlike the GIA dossiers that have sufficient information on them, IGI’s small grading reports that are often offered 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 clarity and color, there might be slight inconsistency between IGI and GIA. While buying an IGI graded diamonds only go for the full IGI reports, not the small ones 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 ideal. It is also important to note that IGI is not as inconsistent in low grade diamonds as they are in high grade diamonds.

Our top advice always would be to go for a GIA graded diamond.  James Allen is one of the best online retailer for buying loose diamonds. 

As you shop for a perfect diamond, we would also advise you get yourself familiar 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 Small IGI Report

Small IGI Certificate