When you are shopping for a piece of diamond jewelry, the grading report is an important document that helps you understand what you are buying. Among other uses, a grading report (certificate) from a reliable gemological lab also acts as a security screen against treated and synthetic diamonds.
Thanks to a series of tests and scientific analysis performed on the diamond during the grading process, it is possible for gemologists to detect the presence of artificial treatments in color or clarity. In short, a grading report not only provides you with a scientific blueprint of the diamond’s properties and characteristics, it also attests to the diamond’s authenticity.
Not all laboratories are created equal. For a consumer, the most important thing is for you to understand the differences between the various gemological institutes. You see, each lab uses its own grading system and nomenclature. As a result, a report from one institute may have show different results from a report issued by another lab for the same diamond.
Let’s examine the differences between 4 of the most major gemological labs in the world – GIA, AGS, EGL, and IGI.
GIA, the Gemological Institute of America, is the leading gemological laboratory in the world. It is the industry’s most trusted and most widely used service. Headquartered in Carlsbad, California, GIA has offices in many cities around the world, employing more than 1400 scientists, educators and certified diamond graders.
Besides gem grading and certification, GIA also provides educational services and carries out intensive research work to keep up with fast changing technologies in the gemological field.
AGS stands for American Gemological Society and it is also a US based laboratory (with main offices in Las Vegas). The AGS laboratory is renowned for their scientific approach and research into diamond cut grading. Instead of using an alphabetical rating system, AGS uses a scale of 0-10 for rating a diamond’s characteristics, with 0 as the best and 10 as the worst.
Like GIA, AGS is also known for their ethical standards and consistency in their grading system. In the US market, the AGS lab is the second most widely used lab service after GIA. They are also globally consolidated through offices in Israel, Belgium, India, China and Hong Kong.
For first timers, the AGS methodology may seem confusing to figure out but once you get the hang of things, it’s pretty straightforward. Here’s an example to help you out: if a jeweler tells you that a diamond has an AGS cut grade of 0, clarity grade of 3 and color grade of 2.5, the equivalent on the GIA scale is a diamond with Excellent cut, VS1 clarity and I color.
EGL is an abbreviation for European Gemological Laboratory. It is a European founded grading agency and has a big global presence – with offices in London, Paris, Tel Aviv, Tokyo, Johannesburg, among others. EGL is known for pioneering diamond grading techniques for stones weighing less than a carat. They are also notoriously known for the introduction of the ‘SI3’ clarity rating for diamonds and have a large market share in Europe.
This is one of the most common scams in the industry where consumers get ripped off. There are many unethical jewelry stores who offer “wholesale deals” with questionable grading certificates designed to misrepresent the diamonds they sell.
An appraisal is usually performed by a trained professional operating in individual capacity and pegs a value to the jewelry. Unlike a report generated by an independent gemological lab, the accuracy of the appraisal is only as accurate as the training, skills and tools the appraiser has.
Note: An appraisal is typically used for insurance purposes and post-purchase follow-ups. It shouldn’t be used as a substitute for a grading report.
And finally, IGI is the International Gemological Institute that is based in Antwerp, Belgium. After GIA, they are actually the 2nd most well-known lab in the world. A significant amount of polished diamonds in the market are actually graded by IGI and they are very popular in Asian countries.
While EGL and IGI are more widely known outside the US, particularly in Europe and Asia, they both operate offices in key cities like New York. As a result, it won’t be uncommon to see retailers carrying diamonds with reports from these labs. Now, I’m going to go on record saying that these are labs I DO NOT RECOMMEND.
It’s ironic in the sense that gemological laboratories were created with the goal to protect consumers by providing reliable information. Yet, I am warning you against them. Find out why on the next page…