For as long as I can remember I have been recommending to any diamond buyer that they buy a diamond with a  GIA “certificate” or “diamond grading report”.  It has recently occurred to me that, while this recommendation my be second nature to someone like me who is involved in the whole diamond trade, the idea of a GIA “certificate” is a concept that is not familiar to the consumer diamond buyer.

The Gemological Institute of America (GIA) is the preeminent authority in determining the quality of a specific diamond. The GIA is an nonprofit educational institute which operates diamond grading laboratories in multiple locations around the world.

Although there are other laboratories that issue diamond grading reports, there are no other diamond grading laboratories or companies that have the same significance with regard to accuracy and respectability.   In fact, other diamond grading laboratories have been the subject of a major class action lawsuit among diamond consumers who alleged that they were defrauded when they purchased diamonds with a certificate that was, in fact, very inaccurate with regard to GIA quality assessment standards.

A GIA “Certificate” or “Grading Report” is a report issued by the Gemological Institute of America with regard to the specifications of a specific diamond. The report represents an  independent and professional assessment of a diamond’s specifications with regard to the actual carat weight, color and clarity of a specific diamond.

The information within the report provides specifications about proportions and other things that provide insight about the “Cut” of a diamond. The GIA has only recently begun issuing a grade with regard to the “Cut” of the diamond.*  Since 2005, the GIA has assigned a “Cut” grade only on round diamonds. Fancy shape diamonds, meaning all diamonds that are not a round shape, are not graded with regard to cut.

The GIA report records many aspects of a diamond’s specifications and scientific measurements which serve as “identification markers” of the diamond.  These “identification markers” identify and differentiate the subject diamond from all other diamonds. For this reason, the GIA report is a record of one specific diamond and thus becomes the “Certificate” for the diamond.

A “GIA certified diamond” refers to any diamond that has been submitted to a GIA laboratory and has been issued a grading report.  This report is in one of three formats.  It can be a full report which contains a diagram and plot of the diamond.  It may be a “Dossier” report which is smaller in size and is usually issued on diamonds which weigh less than 0.99 carats.  A newer report format is referred to as an “E-Report” as it refers to a diamond for which an electronic report is issued without a paper report.  This report, no matter which format, is referred to, interchangeably, as the “GIA Certificate” or “GIA grading report”.

A GIA report is not a statement of valuation. Diamonds of a similar GIA grade are not identical and are not necessarily of equal value.  There are many factors that determine the overall beauty and valuation of a diamond. For this reason, there can be significant valuation differences between diamonds of the same GIA grade.

With regard to diamonds that are not certified by the GIA, it is wrong to believe that such diamonds are less expensive than similarly GIA graded diamonds.  It is my professional belief that most diamonds that are sold without a GIA grading report are sold with inaccurate and exaggerated color and/or clarity grades at higher prices than would otherwise be realized with a GIA grading report.

An additional protection inherent in GIA certification is that the GIA will only offer a diamond grading report on a natural diamond. This eliminates the concern that the diamond may be a laboratory created “diamond” of significantly lesser value.  The GIA grading report will also note if the diamond has been subjected to any treatment or enhancement processes which, in most cases, will effect valuation.

Most diamonds that are sold at mass retailers or typical mall locations are not certified by the GIA.  The reason for this is that the diamonds sold in such stores are usually inferior in quality than that which is typically certified by the GIA.  Also, small diamonds used in jewelry are almost never certified by the GIA .

As I stated at the outset, I recommend that a diamond engagement ring buyer should purchase a diamond that has been certified by the GIA. The GIA diamond grading report provides essential information about the diamond.  A GIA certificate protects the buyer from “puffery” or exaggerated claims made by unscrupulous salespeople.  It protects against synthetic or lab grown diamond imitations as well as non-disclosed enhancements. The GIA report also serves as documentation and identification of the diamond that is useful to its owner with regard to insurance and other matters of ownership.

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For more information on the subject of the new “CUT’ grade, see:   “GIA’s new round brilliant cut grading system sheds light on diamond’s overall appearance”