Diamond Certification

Before purchasing a diamond, you should expect to review a copy of its certificate as proof that it has undergone an unbiased, professional examination.

What is a Certificate?

A diamond certificate, also called a diamond grading report, diamond dossier®, or diamond quality document, is a report created by a team of gemmologists. The diamond is evaluated, measured, and scrutinized using trained eyes, a jeweler’s loupe, a microscope, and other industry tools. A completed certificate includes an analysis of the diamond’s dimensions, clarity, colour, polish, symmetry, and other characteristics. Many round diamonds will also include a cut grade on the report.

Blue Nile Diamonds are Certified

Every loose diamond sold by Blue Nile has been analyzed and graded by either the Gemmological Institute of America (GIA) or the American Gem Society Laboratories (AGSL). These two laboratories are among the most respected laboratories in the diamond industry, and are known for their consistency and unbiased diamond grading systems. Diamonds that are accompanied by these grading reports are the most highly valued in the industry.

In addition to being graded by either the GIA or the AGSL, all Astor by Blue Nile™ diamonds are graded by GemEx - the leader in light measurement - for its brilliance, fire, and sparkle. This second independent analysis guarantees the Astor by Blue Nile diamond's uncommon brilliance.

View Certificates While Shopping

If you are interested in a specific certified diamond at Blue Nile, you can view its certificate on our site before purchase. We offer a variety of grading reports and documentation:

If you are interested in a diamond and a certificate is not available for viewing on the site, simply contact a diamond and jewellery consultant at serviceuk@bluenile.co.uk or 00353-1-899-1351 from Italy, 0800 098 8541 from the United Kingdom, or 00353 1 899 1351 for all other EU countries.