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 Grading Report or Diamond Dossier® is a report created by a team of gemmologists.

Blue Nile Diamonds are Certified

Every loose diamond sold by Blue Nile has been analyzed and graded by the Gemmological Institute of America (GIA). This laboratory is among the most respected in the diamond industry, and is known for consistency and unbiased diamond grading systems. Diamonds that are accompanied by GIA grading reports are the most highly valued in the industry.

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

Learn More About Diamond Quality 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 00800-2583-6453 from Portugal, 0800 098 8541 from the United Kingdom, or 00353 1 899 1351 for all other EU countries.