A diamond certificate, also known as a diamond grading report, is a report created by a professional gemology laboratory. Trained gemologists measure, examine, and assess the diamond in order to produce an unbiased report. A certificate will include details of the diamond’s dimensions, color, clarity, symmetry, and more.

Some of the world’s most respected independent grading labs include the Gemological Institute of America (GIA) and the American Gem Society (AGS). Grading standards vary between labs, making it important to choose a lab known for its rigorous standards.

Diamond certificates give buyers confidence that what they are buying is as described. Assessing value, however, requires an appraisal. Appraisals are usually carried out for insurance purposes.