When buying a diamond a diamond grading report is essential. The grading report or “Certificate” represents an independent analysis of the quality of a diamond. Without such a grading report, one is at the mercy of the seller and assumes that the seller is accurately describing the quality. In many cases, sellers have a tendency to exaggerate the color, the clarity, or the cut proportions of a diamond. Some may do this on purpose; others simply do this because or their own lack of knowledge with regard to accurate diamond grading.
There are several diamond laboratories that offer diamond grading reports – often referred to as diamond “Certificates”. Among the most popular “Certificates” are those of the Gemological Institute of America (GIA) and of the European Gem Lab (EGL).
The Gemological Institute of America, or GIA, is a nonprofit institute dedicated to research and education in the field of gemology and the jewelry arts.Founded in 1931, GIA’s mission is to protect all buyers and sellers of gemstones by setting and maintaining the standards used to evaluate gemstone quality. The institute does so through research, gem identification and diamond grading services and a variety of educational programs. Through its world-renowned library and subject experts, GIA acts as a resource of gem and jewelry information for the trade, the public and worldwide media outlets.
The GIA Certificate is the gold standard of diamond grading. Although diamond grading is not an exact science and GIA grading may not always be perfect, the GIA attempts to be consistent within the framework of the color grading scale and clarity grading scale that GIA created.
One should not assume that every diamond that has the same specific color and clarity grade from GIA is exactly the same. GIA grading is subjective and deals with differences in clarity such as “minute inclusions extremely difficult to locate under 10X magnification” and “minor inclusions somewhat difficult to locate under 10x magnification”. These can be very subtle differences. For the most part, there is not much of a difference in GIA clarity grades in the Flawless or VVS grades. There can be significant differences among diamonds within the “VS”, “SI” and “I” clarity grades. For this reason, often diamonds within these are described as being a “top SI1” or a “weak SI2”.
EGL and most other diamond laboratories are for-profit businesses that are in business to make money. Unfortunately, they make money by issuing inflated or “bogus” diamond grades that do not adhere to GIA standards.
Unlike GIA, which has multiple locations throughout the world but strives to achieve uniform standards for grading diamonds, EGL has several independently operated labs throughout the world. Each has its own standard of how “far off” the GIA standard they are willing to go.
The best of the EGL labs is EGL– USA. There is a lab in New York and one in Los Angeles. I have once or twice seen a diamond grading certificate from EGL-USA that was very close to a GIA standard. In many cases, there tends to be a color grade difference of perhaps one color and a clarity grade difference of the same magnitude.
EGL International, which can be in any one of several locales, is a joke with regard to diamond grading and the Certificates that these labs issue. Color grades may be off by four or five shades – for instance, a diamond that is graded as a “G” color may, in reality be a GIA “L” color. Because of the fewer categories of clarity grades, the clarity grade is usually not off by as many grades as the color, however a variance of two or maybe three clarity grades is not unusual.
Perhaps now you can understand why GIA is the gold standard when it comes to a diamond report or Certificate. To take this a step further, one must understand that if they are comparing GIA graded diamonds and EGL graded diamonds; they are comparing apples to bananas. If one thinks that they are saving money by purchasing an EGL graded diamond, this is usually not true at all. If one were to get a GIA certificate on the EGL diamond they would most likely find that they are overpaying for an inferior diamond.
Such is life. Some people think they have found a way to beat the system. They only understand “low” price. This is the purpose of the non-GIA labs – to give these consumers what they are looking for.
UPDATE: On October 1, 2014 Rapnet banned all EGL grading reports from its diamond database listings. This is a link to the official notice.