What does a diamond identification mark look like?

The identification mark on a diamond looks like the brand identification mark of the diamond processor that inscribed it on the diamond.

See below for, the DeBeers Forever Mark (TM), and the Canada Mark (TM) for diamonds mined in Canada.

Another identification is one you can purchase from the Gemological Institute of America, that they inscribe on a diamond that matches the certificate that you buy which documents the diamonds qualities. You can also read more about this identification, below.