Diamond Certification

Diamond Certificates

What is the purpose of a Diamond Grading Report or Certificate? We believe that when buying a diamond there are a number of factors that come into play but trust and confidence are a big part of the decision making. Most people don’t buy a lot of diamonds in their lifetime and so when they come to make an expensive purchase it can be a little overwhelming. There is a huge amount of information online but often it can be contradictory and confusing. When a client buys a diamond with an internationally recognised certificate it gives them a level of confidence in what they are buying. This begs the question – are all diamond grading reports/certificates equal?

Firstly, lets establish who are the main players?

GIA – Gemmological Institute of America

AGS – American Gem Society

IGI – International Gemmological Institute

EGL – European Gemmological Laboratory

GIA is is the most highly regarded and internationally recognised gemological laboratory. We find that our clients are aware of and have confidence in the GIA Certification and so we do most commonly stock white diamonds that have a GIA certificate.  In most cases these diamonds are also laser inscribed with the GIA Report number which is a further positive for the diamond buying public, increasing their level of confidence. With the cut and finish of a diamond being paramount to the quality and sparkle of the diamond the GIA have also a well recoginsed grade of what is known as a “Triple EX” diamond which is when a diamond achieves an Excellent Grade for Cut, Polish and Symmetry.

AGS – Also has a very good reputation in the industry – equal to that of GIA but it is not as well known in Australia as it is in the United States. The reason we don’t buy more diamonds with AGS Certificate, is simply that most of our clients prefer the GIA Certificate.

IGI – are the largest International Gemological Institute although the work mainly in Europe and the Middle East. The grading is similar to that of GIA and AGS although not always as reliable and are often a little loose on both colour and clarity so where GIA may grade a diamond “F” colour “SI1” clarity it may get either a “E” colour or “VS2” clarity. I would still consider buying a diamond with an IGI Certificate but I would be more inclined to view the diamond prior to purchase.

EGL –   This is the only lab out of the 4 listed that is for profit. This in itself explains a lot. They are chasing market share and have been a lot more lenient on all aspects of grading. This explains why EGL became as popular as it did for diamond merchants, but the fact remains that as a consumer you have to be extremely careful buying an EGL graded diamond.  If I had to estimate the average “upgrade” received from EGL for an identical diamond versus the GIA, I would estimate 2.5 upgrades either from colour or clarity or both.  For example, if the GIA would grade a diamond an “I” colour and “SI2″ clarity, receiving an “H” color and “SI1” clarity would be consider two upgrades (one colour + one clarity).  But if that same diamond received a “G” colour and “SI1” clarity, it would be considered three upgrades (two colour + one clarity).

The entire diamond market is aware of this, of course, and therefore EGL graded diamonds sell at a significant discount when compared to diamonds of equivalent grades certified by the GIA. I wouldn’t rule out completely buying an EGL certified diamond but never without viewing the diamond first. You may think you are getting a bargain but often times you are paying too much for a substandard diamond.


This leads to an important point – you are buying a diamond not a piece of paper. I am amazed by some clients who come in and they hardly look at the diamond but study the certificate intensely. I can’t tell you how many times when clients are looking at two similar diamonds sitting side by side they actually prefer the look of the slightly lower grade and slightly cheaper diamond. Some people may prefer a diamond with a large table, some may prefer how a diamond looks if it a little heavy cut, and some people actually prefer a little colour in a white diamond. Diamond buying comes down to personal choice and I would urge people to be sure the get a Certificate with their diamond but also to have a good look at the diamond to be sure it appeals to their eye.