A diamond certificate (also called a "diamond grading report") is a document containing the characteristics about the diamond that will make up its value. It is the pedigree that goes with the diamond and becomes a valuable document in case of loss because it will ensure that your insurance company will replace your stone with another certified stone of like quality. Certificates are not appraisals since they do not contain any information regarding the value or price of a diamond.
Grading laboratories like the GIA measure and grade diamonds sent to them by wholesalers and retailers. They provide documents called certifications describing the diamond.
The GIA also educates gemologists but just because a gemologist graduated from the GIA educations program does not mean they are somehow qualified to "certify" a diamond. Many diamond shoppers mistakenly think that just because a person graduated from a GIA class, that their opinion in any way "certifies" a diamond. Respected grading labs to not sell diamonds since that would be a conflict of interest.
Beware of retailers who issue their own in-house certifications. We can only think of one reason that a retailer would issue their own certification opposed to an independent laboratory certification, and that is so they can exaggerate the color and clarity grades. The result is you are paying for quality that you are not getting in your diamond. In other words, you buy a diamond with paperwork saying it is G/VS2 quality when, in fact, it is I/SI1 quality by GIA standards.
Any owner of a diamond can submit it to a laboratory for a grading report. The most important service these laboratories provide is an impartial examination and grading of the diamond. They are paid a fee to provide this service but are not biased to grade higher or lower and can therefore be relied on to provide an accurate description of the diamonds vital characteristics.
GIA Gem Trade Laboratories (GIA)
The Gemological Institute of America (GIA), an independent nonprofit organization, was the first organization in the U.S. to provide lab certificates for diamonds. From 1953, when Richard T. Liddicoat created and introduced the International Diamond Grading System™ which has become the standard for diamond grading worldwide.
G.I.A. Gem Trade laboratories issue a diamond grading report. This report provides great details on the diamond and offers a diagram of internal and external characteristics or flaws. It is the fingerprint that uniquely identifies that particular diamond and which could be used later to verify that diamond. Because G.I.A. grades only natural diamonds, those who purchase diamonds with a G.I.A. Diamond Grading Report will be assured that their diamond will not be a synthetic (man-made) or clarity enhanced (fractured filled) diamond. These are the two prevalent problems facing the consumer in this high-tech era.
GIA is a highly respected Lab, but at this point they do not get into cut grading as thoroughly as the AGS. The very rare "excellent, excellent" report from GIA will sell for more or less the same as AGS triple ideal. The diamond industry views the AGS and GIA as the two premier grading laboratories.
Advice: While GIA certifications are highly respected, they do not include many aspects of diamond cut that would be helpful for customers (i.e., crown height percentage, pavilion depth percentage, crown angle, pavilion angle), especially those seeking ideal cut round brilliant diamonds. Try to get a Sarin report along with the certification that shows this information.
AGS Gemological Laboratories (AGS)
The American Gem Society (AGS) was founded in 1934 by Robert M. Shipley, who also founded the Gemological Institute of America (GIA). The AGS is dedicated to consumer protection through established standards of ethical business practices and the continuing education of its wholesale and retail members.
In the early 1990's, an AGS Ad Hoc Committee recommended the development of a Diamond Grading Laboratory to quantify and popularize all of the factors that affect a diamond's value and beauty. In addition to the Carat Weight of the diamond, the AGS' Diamond Grading System rates Cut, Color, and Clarity on a scale of 0 through 10, with 0 being the rarest and most desirable and 10 being the least desirable.
Although the AGS Diamond Grading System was developed in the early 1960's, it took technological advancements in the early 1990's to make it economically feasible to quantify the most important of the 4 C's - Cut. Prior to this time, Diamond Grading Laboratories did not quantify the quality of a diamond's cut.
In 1996, the American Gem Society Laboratory became a reality. Over the next few years, the AGS Ideal 0 cut grade became the new international standard for diamond beauty and value. A diamond that achieves an AGS Ideal 0 cut grade epitomizes the factors that make a diamond maximally beautiful. Those factors are brilliance, dispersion (fire), and scintillation.
Advice: We find AGS to be very good at color and clarity grading. If you want the top grade possible in a round diamond, look for an AGS triple ideal that has ideal proportions, ideal polish and ideal symmetry. This takes all the guess work out of finding a great cut diamond.
European Gemological Laboratories (EGL)
The European Gemological Laboratory, Inc. (EGL) opened its first grading laboratory in Antwerp, Belgium in 1974 and subsequently opened laboratories in New York, Los Angles, Johannesburg, Paris, Istanbul, London, Israel and Seoul. The EGL introduced the SI3 clarity grade that really is just the high-end I1 quality. The EGL certifications include crown height percentage and pavilion depth percentage which are very helpful specifications in determining quality of cut.
In addition to diamond certifications, the EGL also issues a condensed report on a diamond known as a consultation. In this document, only the carat weight, color grade, clarity grade and a plotting diagram is recorded. The difference between the consultation and the certification is that it does not have depth percentage, table percentage, polish, symmetry or fluorescence grades.
Advice: While the vast majority of EGL certifications are accurate with regard to color and clarity, occasionally we see some where the color grades are higher than our determination. It just points out why our personal inspection is so important for every diamond, regardless of the certification.
Professional Gem Sciences (PGS)
Professional Gem Sciences, Inc. (PGS) with offices in both Chicago and Los Angeles, is a full service, gemological laboratory that can identify and certify the quality of your gemstones.
Advice:While relatively new as a grading laboratory, PGS has been found to provide accurate grading and a certification with detail cut information.
International Gemological Institute (IGI)
The International Gemological Institute (IGI) has now developed into the largest independent gem certification and appraisal institute renowned for its quality services, extensive experience and know-how. IGI, the oldest institute of its kind in Antwerp, was set up in 1975 and along with its sister laboratory in New York, is one of the leading gemological institutions in the world.
Advice: We seldom see an IGI certified diamond on the wholesale market. They have targeted the retail market and seem to be the predominate certification in retail mall jewelry stores and large chains. Because we do not inspect many IGI certified diamonds, we withhold judgement as to their consistency and accuracy.
Diamond High Council (HRD)
The Hoge Raad Voor Diamant (The Diamond High Council) is best known as the HRD. The officially recognized representative of the Belgium diamond trade and industry, the HRD headquarters are located in Antwerp, World Diamond Center.
Global Gemological Laboratories (GGL)
GGL is scientific diamond grading laboratories. They appear to be used by a limited number of retail stores (i.e., Kay Jewelers, Reeds, and Sam's Club). Since they grade stones mainly for a few large customers, we suspect they have "incentive" to be generous with their grades. If something is on the edge between two grades (according to whatever their definition of those grades is) they will likely definitely give it a more positive grade that favors their client base.
Once again you have to ask yourself why these few retailers would choose to use this company rather than the AGS, GIA, EGL, HRD or even IGI grading laboratories. Our guess is that the GGL reports are not nearly as strict as the more recognized certifications and that the differences will always favor the retailer, not the consumer.
National Gemological Laboratories (NGL)
National Gemological Laboratories, Inc., located in midtown Manhattan, offers a wide range of analysis in all matters relating to jewelry. National Gemological Laboratories is an Accredited Facility that is licensed by the New York City Department of Consumer Affairs and employs GIA Graduated Gemologists. NGL provides Certifications and Appraisals for diamond and colored stone jewelry and is only open to the trades, such as cutters, importers, wholesalers, and jewelers.
You will see this paperwork almost exclusively with diamonds advertised on eBay (many of which seem to be clarity enhanced). You have to ask yourself why these few retailers would choose to use this company rather than the AGS, GIA, EGL, HRD or even IGI grading laboratories. Our guess is that the NGL reports are not nearly as strict as the more recognized certifications and that the differences will always favor the retailer, not the consumer.
The NGL initials are easily confused with the Northern Gemological Laboratories (NGL) in the United Kingdom and the Northwest Gemological Laboratory (NGL) in Bellevue, Washington which seem to have excellent reputations.
We also find it interesting that these "grading certificates" have a retail value on them, yet there is no mention that this is an appraisal. In fact the fine print says the report is not a guarantee, valuation, nor an appraisal. If it is not a valuation or appraisal, why does it have a retail value stated on the document?
Copy Cat Paperwork
There are numerous laboratories and companies that have created documents that look very similar to the format of the GIA diamond grading reports. They also have names and initials that are so similar to GIA that it is obvious they are trying to look like GIA documentation. This paperwork is prevalent on eBay and in jewelry stores across the country.
Our concern is that consumers are being deceived by this paperwork and think it has the same validity and accuracy of the GIA or AGS grading laboratories. There is only one reason we can think of for retailers to use these "copy cat" certifications and that is they are too generous in their color and clarity grading. If these documents are one or two grades off in their color and clarity grading compared to GIA standards and consistency, retailers are able to make undeserved profits at the consumer's expense. Here are some companies that have names and paperwork that are uncannily similar to the GIA or AGS.