You want one of these. It's a professional opinion on the characteristics of your diamond. The grading report is an impartial judgment of the characteristics and quality of each diamond. When you buy a diamond it should come with a report, which will tell you all of the particulars of the stone, from what colour grade it is to the amount of fluorescence it has. Some grading labs have better reputations than others, with GIA being the most reputable.
GIA is the world's oldest, largest, and one of the most respected independent laboratories. Unlike some other labs, GIA is not owned or partially owned by diamond wholesalers or retailers, and is a non-profit organisation. GIA actually developed the "4 C's" diamond grading system (used almost universally today) to provide truly objective standards in the evaluation of a diamond.
At ILLARIY every certified diamond is accompanied by its GIA Grading Report or Dossier when they are over 0.30ct weight of carats.
GIA DIAMOND GRADING REPORT
GIA DIAMOND DOSSIER
For some smaller diamonds, an abbreviated form of the GIA Grading Report is often used, called a GIA Dossier. This condensed report offers the same information as the GIA Grading Report listed above, with the exception of a diamond plot, since the individual flaws are less important in smaller stones.
Every diamond that has been issued a GIA Diamond Dossier will have the report number laser inscribed on the diamond's girdle. This added security allows the purchaser to confirm the identity of the diamond at all times.