A certificate is actually the ""blueprint"" of a loose diamond. It is also called the diamond grading report or diamond dossier. It tells you the diamond's exact measurements and weight, as well as the details of its cut and quality. The certificate points out precisely all the individual characteristics and facets of the stone. The certificates also serve as proof of the diamond's identity and value.

A certificate, however, is not the same thing as an appraisal. A certificate describes the quality of a diamond, but it does not place monetary value on the gem. The certificate may help determine the diamonds market value, but does not give the appraisal. There are many diamond grading labs that issue certificates such as the Gemological Institute of America (GIA) and the American Gem Society (AGS), the two most widely regarded and recognized diamond grading labs in the world.

There are many diamond grading labs in operation, many of which produce their own grading reports. Different labs have different grading standards, and some labs will be more lenient with their standards compared to others.

Shopping around for graded loose diamonds allows you to make an informed choice about your selections. You can compare one diamond with a particular weight and quality with other loose diamonds of similar weight and quality to determine which has the better value.

When purchasing loose diamonds, it is always safe to do so in stores that give out a report for every loose diamond purchased. This way, one can make sure that the diamond is genuine. Some diamond stores actually boast of selling diamonds that are accompanied by a lab report from GIA or AGSL, labs that have consistently demonstrated their commitment to high standards. Some lab reports are also ready for online viewing for the virtual shoppers.