What is the difference between a Diamond Certificate and an Appraisal?

A Diamond Certificate is a document issued by a Gemological Laboratory describing a loose diamond. The laboratory will not issue certificates on diamonds that are set in a mounting. A Diamond Certificate issues a "grade" indicating the physical properties of the diamond "at the time of evaluation," and retains its accuracy, and value to the purchaser, over a long period of time, assuming the diamond does not chip or is not otherwise altered.

An appraisal can be performed on a loose diamond, a mounted stone, or a piece of jewelry. If the stone is not loose, the physical properties are estimated using various estimating techniques. Most importantly, an appraisal indicates the dollar value of the piece under consideration, most often for insurance purposes, and that value can change considerably over time.

Many people make the mistake of using an in-house appraiser to evaluate the purchase price of their diamond. This is a mistake, for several reasons. First, appraisals are often over-estimated, and are therefore a poor gauge of a diamond's value or price. Equally important, in-house jewelers may often be biased.

To further complicate matters, many people have become more educated when it comes to buying diamonds, and have learned the importance of having a GIA certificate. What they have not learned, unfortunately, is how to differentiate between a GIA GTL (Gem Trade Lab) Grader and a GIA G.G. or Graduate Gemologist. Many assume that getting an appraisal by a GIA gemologist is the same as getting a GIA Certificate. Some unscrupulous jewelers further that illusion in their dealings with customers.

The GTL (Gem Trade Lab) Grader is a GIA employee who performs the diamond grading for the Gemological Institute of America. A GIA Graduate Gemologist, on the other hand, has simply passed the GIA Diamonds and Colored Stone course.

The GTL Grader is far better trained in grading and usually has far more experience than a Graduate Gemologist. Further, the GTL Grader does not have the same vested interest in the outcome of the grade of the stone being evaluated.