Before purchasing a loose diamond or diamond ring, you should expect to review a copy of its certificate, as this is your guarantee of the quality and value of the diamond.

A diamond certificate, also called a diamond grading report, diamond dossier, or diamond quality report, is a document created by an independent gemological lab or institute, where the diamond is scrutinized under a microscope to analyze its carat weight, clarity, cut, color and other characteristics.

Some jewelers offer diamonds graded by both the GIA and the AGL, as these are the two most respected diamond grading laboratories in the world. Unfortunately, these two grading laboratories grade diamond cut differently. This can make it difficult when comparing diamonds that have grading reports from different diamond laboratories. As such, some jewelers present a consistent set of measurements for diamonds with AGL and GIA grading reports.

Some more common grading reports are as follows:

• GIA Diamond Grading Report
• GIA Diamond Dossiere
• AGL Diamond Quality Document
• GCAL Certificate of Authenticity