GIA vs. IGI vs. AGS
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Diamond Certification – GIA vs. IGI vs. AGS

Diamond is a gemstone that needs no introduction. A diamond’s story begins over many miles below the earth, and each diamond has its own journey through time. From the mine, to showcase, to that jewelry box. Whether it is the everyday diamonds to occasion wear, to that cocktail party, each diamond has its own tale of shine. There have been much new information and rising concerns that have led us to definitely look beyond the shine so that we get our money’s worth. 

Buying a diamond is not a small investment. Before investing in a diamond, we must take various things into consideration. The carat, the cut, the color, clarity, and the list goes on, all so that it’s worth the money and shine. Shoppers are now more aware than before and always opt for a diamond certificate along with their purchase. But, they are often confused with the various options of labs in the market. For starters, not all certificates are the same! As the labs differ, so do their grading practices and ethical standards.

GIA vs. IGI vs. AGS

Source: vascoassets.com

A diamond certificate is a crucial document that accompanies your diamond on purchase. It holds details of your diamond that contribute to its value. If the grading of your diamond is not done correctly, you will end up overpaying for a low-quality diamond. Thus, it is advisable to prefer labs that are credible and accurate and gives you that confidence.
While choosing the right lab certification for your diamond, here are three things to consider which are necessary – 

  1. Accuracy –The characteristics of a diamond determine its value. Accuracy in the grading process is to give the right grade to the diamond after analyzing its features. This gives you an assurance that the grades assigned to the diamond are precise, and you are getting exactly what you paid for. The grades in your diamond certificate must justify its quality. Not less, not more. Diamonds graded by IGI and AGS almost always lack accuracy. An E colored SI1 diamond would look duller, faded, and included if it is certified by IGI or AGS when compared to a stone of the same grade, certified by GIA. Thus you end up to a lower quality diamond that, in reality, is worth much lesser. 

  2. Consistency – Accuracy backed by consistency equals reliability. A diamond certificate is an added assurance to your purchase, which cannot be possible if a lab is not consistent throughout its grading process. While they say grading is subjective, and one grade up or down is accepted in trade, the grades highly vary in the case of many labs.
    A common issue with IGI or AGS is that the same diamond will be assigned different grades when submitted for a recheck in the same or different branches. Another issue with IGI’s grading process is that every branch of IGI grades differently that breaks the consistency and standardization. Without consistency, it is difficult to gauge and trust the diamond’s specification that comes with an IGI or AGS certification.

  3. Avoid labs with loose grading – If labs are lenient while grading a diamond, it means that the real quality of the diamond does not match the details specified on the certificate. This ends up with you overpaying and helps some retailers make a massive profit out of your purchase. Retailers know that inferior diamonds are not preferable. Thus, with an inflated grade, the same diamond would get a higher price. Hence, they try to convince the customers to prefer one certificate over the other to benefit out of lenient grading. IGI and AGS grades are known to be more forgiving because of its loose and lax grading practices. 
    Let’s consider the color, for instance. If an IGI or AGS certificate mentions F color in its report, chances are that the diamond would get an ‘I’ if appropriately graded. Thus, you are paying for a grade that is not authentic, and so you end up getting a much lower quality diamond at the same price.
    Summing up the above points, choosing a certificate along with your diamond among all the options in the market will require research. Reliability in terms of grading practices and ethical standards really matters as choosing a certificate would help you determine your diamond’s worth. Your diamond should be exactly what you paid for, and hence, choosing IGI or AGS are not recommended. 

 We have taken a few diamonds from JamesAllen.com to compare…

GIA 0.51 CARAT I-SI2 ROUND DIAMOND

IGI 0.51 CARAT I-SI2 ROUND DIAMOND

AGS 0.51 CARAT I-SI2ROUND DIAMOND

GIA 0.70 CARAT H-SI1

IGI 0.70 CARAT H-SI1

AGS 0.70 CARAT H-SI1

GIA 0.50 CT I- SI2

GIA0.90 CT H

IGI 0.50 CT I- SI2

IGI0.90 CT H


We have picked different sets of stones from JamesAllen.com to compare. This will help to understand the difference between GIA, IGI, and AGS labs in terms of grading standards. Although IGI and AGS ‘claim’ to follow the same grading standards as GIA, it’s obvious from the pictures above that they do not since all the stones have the same grades but clearly look different. We saw a massive variation in the quality of the diamonds in terms of color and clarity. This indicates that there is a considerable chance of customers being ripped off as the diamonds graded by IGI and AGS look really dull and off when compared to GIA. That means you are paying the same price and getting a diamond that is duller and has more inclusions. The practice of lenient and inflated grades can cost you a fortune. 

GIA vs. IGI vs. AGS

Source: economictimes.com

If you look carefully, you would observe that the grades of IGI and AGS stones are undoubtedly inflated. The 0.51 CARAT I-SI2 round brilliant of IGI and AGS is shifted more than 1 grade higher in terms of both color and clarity. Those stones are definitely of a lower quality if you compare it against the one graded by GIA. This means that though you could have got a much better-looking diamond at that cost, you ended up overpaying for an inferior diamond. Thus, believing the authenticity and credibility of the certifications by labs like IGI and AGS is not advised. 

Also Read: Classifying Diamond’s Quality Using the 4Cs

Retailers know that a diamond of a lower grade is not preferable for most of their customers. Hence, many retailers opt for labs that are lenient with their grading process. The grades mostly do not match the quality of the diamond, and thus, retailers make money out of your ignorance. Retailers also suggest opting for IGI and AGS because their certificates are cheaper. But, in reality, that would incur a loss in the long run due to its inflated grading system. If you compared the color of the 0.90 Carat IGI H colored diamond against the 0.90 Carat GIA H colored diamond, you would instantly see the difference. The difference is so evident that you do not even require a loupe to tell the variation. The same goes for the clarity of the 0.70 Carat H-SI1 diamond of IGI and AGS against the one graded by GIA.

 Opting for labs like IGI and AGS is scary because it will turn out to be a big rip off. You will end up with a diamond that is far inferior and which would cost lesser if graded accurately and ethically. Diamond certificates also highly contribute when you consider selling your diamond. Though a diamond certificate is not the same as a valuation or an appraisal certificate, it certainly plays a vital role in contributing to a diamond’s value. It is advisable to be careful while planning your purchase. IGI and AGS are strictly not recommended as you might just end up overpaying.