The IGI VS The GIA & The AGS

You may be well versed in the Four C’s of diamond buying (cut, color, carat and clarity), but diamond certification is just as important. Understanding certification is a vital step in buying a beautiful diamond for the right price. A diamond certificate provides a determination of whether a stone is a natural mined diamond, or one that is lab grown or artificially treated in some way. Detailed information allows you to know exactly what you are buying. This may seem simple enough, but there are significant variances between diamond laboratories, with some proving far more reliable than others.
One diamond lab which has developed a mixed reputation is the IGI (International Gemmological Institute). In this article, we will compare IGI to two of the leading diamond labs, the GIA and the AGS, and illuminate the differences between the most trusted labs and the IGI.
X-Prong Trellis Solitaire Engagement Ring
X-Prong Trellis Solitaire Engagement Ring

What is Diamond Certification?

A certified diamond is analysed by specially trained experts in a specially equipped laboratory where it is put through a series of tests; these tests will ultimately determine the quality grades of the diamond. A trusted diamond certification will come from a third party – an independent company not involved in buying or selling diamonds and presumably with no incentive to understate or overstate its quality. The sole purpose is to provide an accurate analysis of the diamond and its properties. The gemologists’ findings will be listed on the diamond certificate, usually with illustrations that show the proportions of the diamond and the location of any inclusions or blemishes. It is a scientific report that also attests to the diamond’s authenticity and quality.
Accuracy and consistency are key components in a diamond certificate so finding a lab which can deliver these results is essential.


GIA Logo
Image Courtesy from The GIA
Since it was founded in 1931, The Gemological Institute of America has been widely regarded as the most trusted gem lab in the world. They literally invented the basic grading system that is used by most other serious gemological laboratories. The GIA is headquartered in California but they have labs across the globe. They are known for their strict grading standards and advance analylics which ensure consistency throughout their process. Furthermore, they have education and research centres which are dedicated to continuing research within the field. Their color grades run from D-Z, clarity from FL-I2, and their cut grades run from Excellent to Poor.
GIA Cert


AGS Logo
Image Courtesy from The AGS
The American Gem Society was established in 1934 (a sister organization to the GIA) and features another US based gemological laboratory. While the GIA is known for creating the four C’s, the AGS is best known for their detailed and scientific analysis of diamond cut quality and light performance. Their grading is done on a scale of 0-10 with 0 denoting the highest quality (Ideal) and 10 the lowest. The AGS delivers a comparable level of 4C’s grading consistency as the GIA, but are superior when it comes to cut grading. Their research and focus on the complexities of diamond cut results in a more strict and accurate grade. The AGS system uses sophisticated computerized ray-tracing to analyze the light performance of the diamond.
AGS Cert
Both of these labs will give you an accurate and reliable certificate for your diamonds, but when it comes to diamond cut, the AGS is able to provide details that the GIA does not reach. If you are considering ideal or super-ideal cut diamonds, they are likely to carry an AGS certificate, as only this lab has the resources and advanced grading framework in place to truly dig into the details of cut and light performance.


IGI Logo
Image Courtesy from The IGI
The International Gemological Institute is based in Antwerp, Belgium and has facilities around the world. Although you will find IGI certified diamonds in countries all over the globe, these certifications are more widely relied upon in Asia and Europe. IGI reports are considered by some in the trade to be less reliable that GIA or AGS, especially by merchants operating in the US. IGI tends to service large volume jewelry chains, and therefore issues thousands of reports on commercial quality, mass market diamonds. As a result IGI tends to offer their service at cheaper rates than either GIA or AGS.
IGI has a big footprint and are involved in a number of activities in addition to grading diamonds. They also have very respected schools training gemmologists, as well as rough diamond grading and CAD design.
IGI Cert

Problems with the IGI

One of the big problems with the reputation of IGI in the US is their issuance of diamond reports with inflated valuations. Diamonds sold in prominent big box stores are marketed with IGI reports featuring “appraisals” that indicate the diamonds are worth many times actual replacement value. While IGI defends this practice by saying that insurance policies bound with these reports protect customers who may be in a position to have to pay a premium when they incur a loss, the fact is that many customers are predicating their purchase on these misleading valuations. It also means that the customer will likely pay higher insurance premiums than necessary. This practice calls into question the ethics of IGI, greatly damaging their reputation and tainting their overall grading practices. They also do programs for finished jewelry manufacturers that have a similar negative connotation for many in the market.
GIA and AGS do not suffer from this image problem as they stay true to their missions of consumer education and protection.

The IGI is not Equal to The GIA or The AGS

We pride ourselves on integrity and provide extensive information and education on the diamonds we offer. We rely exclusively on AGS and GIA as the most trusted, most capable, and most consistent of all laboratories. The IGI and IGI certified diamonds have a place in the market, but in many ways are not comparable to GIA or the AGS. There is fragmentation within the IGI network. Certain IGI labs have different practices and offer specialized services such as the valuations discussed above. This gives rise to inconsistencies in their reporting which erodes trust in their documents. For instance, IGI reports from certain labs in Europe or Asia might be more reliable than others, leaving consumers without a clear understanding of their standards. In 2018 a controlling interest in IGI was purchased by a Chinese conglomerate. It remains to be seen how this development will affect the operations and reputation of IGI.
The AGS and GIA are the gold standard of diamond grading and certification. Internationally recognised for their consistency and accuracy they provide buyers with detailed information pertaining to their diamond, allowing them the best opportunity to fully understand their diamond. The IGI does not enjoy the same reputation, particularly in the American market. While they are a legitimate independent lab (preferable to in-house certification), with so many beautiful GIA and AGS diamonds available, buying an IGI certified diamond seems to most US consumers like an unnecessary risk. For the Ultimate Diamond Pedigree And Conclusive Imaging Proof Of Performance choose an A CUT ABOVE® Round Hearts and Arrows Super Ideal Diamond:

Be Inspired By Our Designer Engagement Rings

Find the perfect Designer Ring for your special diamond by clicking the links below, and let us build the ultimate ring for the love of your life!