A Diamond Certificate is a document issued by a Gemological Laboratory describing a Loose  Diamond. The laboratory will not issue certificates on Diamonds which are set in a mounting. A Diamond Certificate issues a “grade” indicating the physical properties of the Diamond “at the time of  evaluation”. A certificate is a document which retains it’s value 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 jewelry. If the stone is not loose, the physical properties are estimated using various estimation techniques. Most importantly, an appraisal  indicates the Dollar Value of the piece under consideration. Obviously, the Dollar Value can easily change considerably over a relatively short period of time. Appraisals are most often used for insurance purposes.

Many people make the mistake of using an in-house appraiser to evaluate the purchase price of their Diamond. This is a big mistake. Firstly, appraisals are often  over-estimated, and are therefore a very poor estimation of price. More importantly, any in-house Jeweler may be biased.

To further complicate matters, many people have  become more educated when it comes to buying Diamonds, and have learned that it’s important to have 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 attempt to further that illusion.

The GTL (Gem Trade Lab) Grader is a GIA employee who performs the Diamond Grading for the Institute. 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 G.G. Further, the GTL grader does not  have the same vested interest in the outcome of the grade of the stone they are evaluating.