IGI vs GIA | What is the Difference?

The Gemological Institution of America was founded in 1931 as a non-profit institution dedicated to researching, educating, and grading natural gemstones. It developed a standard for everyone in the diamond industry to apply as a unified methodology for grading diamonds and other gemstones.

Due to their dedication and hard work, GIA introduced the International Diamond Grading System (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. It has nine laboratories and four research centers in 13 countries.

GIA graded reports can be verified here.

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 has major operations. The company also has offices in diamond centers worldwide, such as New York, New Delhi, Surat, Hong Kong, Dubai, Shanghai, and Tel Aviv.

IGI, which has more than 650 gemologists and jewelry professionals, has been trying to establish itself as a well-known diamond grading lab.

Buyers can verify IGI graded diamond reports here.

In our experience, IGI is not as strict as GIA when grading natural diamonds, but this does not mean they should be ruled out entirely. With an informed decision, it is still possible to acquire a good-quality IGI graded diamond.

Because IGI is loosely structured globally, slight inconsistencies among its labs may exist, depending on their location.

As a rule of thumb, it is safe to assume a one-grade color inconsistency between GIA and IGI graded diamonds in D-I color. This inconsistency is much minor for J and lower color range diamonds. One can also expect a one-grade clarity inconsistency in IGI and GIA graded diamonds, especially in high investment-grade diamonds with D-F color and Flawless to VVS diamond clarity range.

Be 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 low-clarity grade IGI diamonds are eye-clean with no obvious noticeable inclusions.

On the bright side, around 10-20% of IGI graded diamonds might be consistent with how GIA would grade them. How? Human beings grade diamonds; individual gemologists grade and then cross-examine them. Therefore, some gemologists in IGI may be as strict as those in GIA. The problem is that they do not grade diamonds consistently across the organization as GIA.

The moral of the story is that unless it is an excellent deal, you are probably not getting a reasonable price on an IGI graded diamond—it is just graded higher than it would be in a GIA report.

Think about it; every dealer knows 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 would also sell fast. So, what is their incentive to grade the diamond by IGI? Deep down, they know it is more lenient than GIA and would give more favorable results.

When buying IGI and GIA graded diamonds, pay attention to the types of reports available:

• GIA offers diamond dossiers, typically for small diamonds, and full grading reports for diamonds of any size.
• IGI provides two types of diamond grading reports: mini-reports and full grading reports.

Unlike GIA dossiers with sufficient information, IGI's mini-grading reports, often issued to vendors in shopping malls, are limited in providing sufficient data about a diamond, especially its cut quality.

When considering IGI graded diamonds, buy one with a full IGI report issued by their well-established labs in the U.S. or Antwerp.

 

In addition to the 4Cs, diamond buyers should pay close attention to the following details in a grading report (full grading reports issued by both GIA and IGI should have this information):

Measurements: These details show a diamond's surface size and can help you determine its length-to-width ratio simply by dividing the length by the width of the diamond.

Fluorescence: This is considered the fifth C in a diamond. As such, buyers must not ignore it. It is best to avoid fluorescence; no faint or medium blue can be acceptable or helpful in diamonds that are H or lower in color.

Inscription: This section will show if the diamond grading report number is laser-inscribed on the diamond’s girdle (it is not necessary but is offered as an additional option for authentication purposes).

Comments: This section is critical for finding additional insights about the diamond’s clarity type, enhancements, and other details.

Proportions: This section's details are crucial for assessing the diamond's cut quality. It shows the precise proportions of a diamond’s cut. Read our guides for each shape to evaluate the cut quality of the diamond.

Clarity Characteristics: This section details the type of inclusions and their locations in the graded diamond.

While IGI is a reliable lab, it is still not as consistent as GIA, though we should not entirely rule out the former. Instead, the best approach could be working with the assumption that there might be a slight inconsistency between IGI and GIA regarding diamond clarity and color.

When buying IGI graded diamonds, buy ones with a full IGI report, not the mini-reports, as they do not have any information related to the cut or fluorescence. Moreover, purchasing an IGI diamond with lab reports from their more established U.S. and European labs might be a good idea. It is also important to note that IGI is more consistent with low-grade than high-grade diamonds.

Our best advice is to choose a GIA certified diamond and avoid the risk altogether if you are a first-time buyer.

As you shop for a perfect diamond, we suggest you familiarize yourself with the seven factors affecting its price and the four scenarios buyers consider while shopping.

The seven factors include diamond shape, carat weight, color, cut, clarity, fluorescence, and certification.

Finally, here is a list of our top-rated online websites for buying diamonds.