Commonly referred to as the '5th C' of the famous 4 C's of diamond grading, independent and reputable certification is without a doubt the most important. The job of a gemological laboratory is to impartially grade the authenticity and quality of your diamond without any bias or relation to the jewelry retailer.
An independent and reputable diamond certificate will ensure you get accurate carat, color, clarity and cut grading on your diamond. A diamond that is sold without such certification will be over-graded and over-priced for the real quality of the diamond.
This is your only guarantee of the quality of your diamond.
The GIA or Gemological Laboratory of America is the world standard in grading. The color, clarity and cut grading that we are all used to using is the GIA grading. As the standard for grading, they also provide the strictest and most accurate grading.
GIA graded diamonds typically come with the certificate serial number laser inscribed on the girdle of the diamond. This serial number - also on the certificate itself - can be verified on the GIA website.
Note that this isn't the same as a GIA graduate gemologist who may have been educated by the GIA but isn't subject to GIA lab standards.
IGL and AIG Certification
IGL and AIG are an independent gemological labs that also grade clarity enhanced diamonds, which the GIA don't. IGL have locations in all the major diamond districts of the world - in Israel, New York, Antwerp and more.
Typically, their grading isn't as strict as GIA grading and you can expect a 1-2 grade discrepancy between color and clarity grading between GIA and IGL or AIG.
At Shiree Odiz, the vast majority of our 100% natural loose diamonds come with GIA certification while our natural clarity enhanced diamonds will come with IGL or AIG certificates as specified in the product description.