Many lab graded diamonds are laser inscribed on the girdle edge of the diamond with the number for the corresponding diamond grading report,  however the fact is that many more diamonds have never been lab graded or inscribed.  Perhaps you own a diamond that you would like inscribed to assist with identification.

If you own a lab graded diamond which is not inscribed there are a couple of options available to you.  The first option would be to send the unmounted diamond back to the laboratory which originally graded the diamond and pay to have the diamond re-graded and inscribed with the new lab report number.  Most gemological laboratories will not inscribe a diamond without grading the diamond again because it is possible for the characteristics of the diamond to have changed since the diamond was graded originally.

The second option would be to contract the services of an independent company that provides inscription services.  In most cases these companies will not inscribe the logo of the laboratory which graded the diamond for reasons pertaining to trademark infringement; however they will inscribe the number of the lab report which is enough to provide a reasonable relationship between the diamond and the lab report.