A certificate is a "blueprint" of a
diamond, it tells you the diamond's exact measurements and weight, as well as
the details of its cut and quality. It precisely points out all the individual
characteristics of the stone. Certificates also serve as proof of the diamond's
identity and value.
A certificate is not the same thing as an appraisal.
A certificate describes the quality of a diamond, but it does not place a
monetary value on the gem. An appraisal places a monetary value on your diamond,
but does not certify the quality of the diamond.

Who Issues Certificates?
There
are many diamond labs that issue certificates, but the Gemological Institute of
America (GIA) and the American Gem Society (AGS) are the two most widely
regarded and recognized diamond grading labs in the world.
And while
there are many other diamond grading labs in operation (many of which produce
their own grading reports), dfferent labs have different grading standards, and
some labs will be more lenient with their standards than others. Therefore, we
recommend buying from a diamond jewelry store that offers GIA or AGS certified
diamonds, as these labs have consistently demonstrated their commitment to high
standards. If you do elect to buy a non GIA- or AGS- certified diamond, always
ask for credentials of the certifying lab.
Why Do I Need a
Certificate?
Shopping for certified diamonds allows you to make an
informed choice about your selections, and to comparison shop. You can compare
one diamond with a particular weight and quality with other diamonds of similar
weight and quality to determine which is the better value.