Did you ever wonder why two diamonds certified by different laboratories could have a tremendous difference in price? This article is going to explore some of the differences and try to explain why prices vary so much. There are many laboratories in many countries that grade diamonds for quality. Some strictly report quality and some offer appraisal services. On the retail level, these laboratories are used to create confidence and imply value; however, inside the industry it is well known that some laboratories do not grade quality as strictly as others. It is also known that some are more lenient on other categories of grading. Armed with all this information and the desire to create profit margins, many in the industry will send diamonds to specific laboratories in an effort to get the highest grade. By doing so the illusion is that the same diamond grade is cheaper than other diamonds graded by more reputable and reliable laboratories.
What does this mean to the consumer?
It usually means “You get what you pay for”. If you want to be sure you are get what you pay for, it would be wise to get a report from a lab recognized worldwide as consistent and respected.
Here’s a list of the major laboratories.
1. Gemological Institute of America (GIA)
2. Hoge Raad voor Diamant (HRD)
3. American Gem Society (AGS)
4. European Gemological Laboratories (EGL)
Are there others? Sure. These are the most widely used and recognized.
GIA and EGL have multiple locations, and with multiple locations come more opportunity for discrepancies. GIA seems to have managed to maintain their stature and reputation within the industry. The same cannot be said for EGL. HRD is in Belgium and AGS is in the United States.
All the labs provide the basics according to their standards. This includes what many refer to as the 4 C’s (Carat, Color, Clarity, and Cut). Each lab addresses each of the 4 C’s differently. By comparing the labs with respect to the 4 C’s, it will become apparent how those in the industry take advantage of the each.
The “Carat” part is the most straightforward. All labs generate a carat weight for a diamond using a calibrated scale. There should be no variations from one lab to the next. Weight is reported with an accuracy of 0.01 of a carat.
The “Color” of a diamond is where we start to see differences in the labs. GIA may have the narrowest divisions between color grades starting from white to yellow. HRD and AGS stretch the divisions slightly. EGL can be tighter in the higher whites sometime, but have a much broader tolerance for color in the white to slightly yellow range. Here are a few examples of how this plays out on paper. A diamond graded K color at GIA will probably get J at HRD and AGS while at EGL at least a J and possibly an I color. In the higher whites, there is less room for movement. Generally, D or E colors are fairly consistent; however, there have been occasions when EGL graded high colors stricter than GIA. As a result, when certifying lower colors EGL would create the greatest potential for profit and value.
When looking at “Clarity”, there is even more confusion. All labs start with Flawless or Loupe Clean and end with I3. The most significant differentiating factor in clarity is that EGL incorporates an additional clarity grade called SI3 which no one else recognizes. It does however have some validity, mainly because of the exaggerated price difference between an SI2 and an I1. SI3 bridged the gap between the very generous SI2 and a very critical I1. There was always a premium for a very nice imperfect diamond, but now it can be confirmed and computed. In general, for the rest of the clarity grade system, GIA and HRD tend to be stricter through the higher qualities. Once again, if a dealer is going to spend the money for a certificate for a lower quality diamond, EGL would be used in an effort to avoid getting an I1 grade, as well as for cases where the diamond might be on the border of a higher grade.
The “Cut” part of this equation was the last to be added to the certificates and probably the most complex. It involves a largely subjective interpretation of what angles, percentages, and proportions of the modern round brilliant create the most scintillating and appealing effect. Polish and symmetry take on a new importance now also since they are factors that affect the cut grade. GIA, HRD, and EGL use “Excellent” to “Poor” to describe cut, polish, and symmetry. AGS uses 0-5. AGS may be the most discerning when it comes to this category, followed by HRD, GIA and lastly EGL. The term “Ideal” is used by some to describe a specific type of cut called Tolkowsky, named after its creator. Keep in mind that much of this is marketing. Cut is very important however wide tolerances can be allowed and still have a beautiful lively diamond.
In conclusion, research the labs for yourself. Links to all 4 labs are available on my website, as well as a few others. Personally, I choose to work only with GIA graded diamonds. They may cost a bit of a premium but I never have to apologize for quality discrepancies. My philosophy is that if the quality is not good enough for a GIA report then it’s probably not worth spending the money on any certificate. Inside the industry, dealers will not dispute quality nearly as much when a diamond is graded by GIA, and to an extent HRD as well. It is not uncommon for a sale to take place between dealers “sight unseen” with GIA graded stones. With other labs this is not a realistic possibility. I cannot express enough that anytime a diamond is certified by anyone other than GIA, I insist on seeing the stone before I make a purchase or even offer.
I have been directly involved in the diamond industry since 1987 in many areas. I am writing from experience, in terms I hope the average person can understand and gain from. I hope this article has provided some helpful information. It was written to protect consumers who may be considering a diamond purchase. If anyone has any questions or comments feel free to email me by visiting my website. Please look for future articles I will be writing regarding other areas of the industry that I believe require some clarification and perhaps even exposure.
H. B. Harris
Round Diamond EGL
Round Diamond EGL
Round Diamond EGL