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

tips & hints
What is the difference between the AGSL and the GIA certificates?
The Gemmological Institute of America (GIA) and the American Gem Society Laboratories (AGSL) are among the most respected laboratories in the diamond industry. Both laboratories are highly respected due to their consistency and their conservative grading standards. There are minor differences in the Read more...
Does Blue Nile carry diamonds certified by other laboratories, such as IGI or EGL?
The International Gemmological Institute (IGI) and the European Gemmological Laboratory (EGL) are two other independent diamond grading laboratories. Blue Nile does not carry diamonds certified by these laboratories. Read more...
What is a GCAL Report?
When you purchase a Blue Nile Signature Collection diamond, you will receive an additional certification from the Gem Certification & Assurance Lab (GCAL). This secondary certificate verifies that your diamond meets all the specific quality requirements of the Read more...
Does Blue Nile offer an appraisal for my jewellery purchase?
Blue Nile includes an appraisal with diamond engagement rings, any jewellery set using our Build Your Own Diamond Jewellery® feature, and most other jewellery over $1000. Read more...
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additional tips

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 jeweller’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.

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 consultant at serviceuk@bluenile.co.uk or 00353 1 899 1351 from Italy, 0800 206 1160 from the United Kingdom, or 00353 1 899 1351 for all other EU countries.

More About Cut

How Does Blue Nile Grade Diamond Cut?

Blue Nile uses cut grades provided by GIA and AGSL whenever these are available. Many diamonds graded by the GIA prior to January 1st, 2006 do not have such grading. If a cut grade is not provided by one of these laboratories, Blue Nile defaults to a proportion system that uses measurements of depth and table to determine the amount of brilliance in a particular diamond’s cut. Learn more about how Blue Nile provides cut grades that allow you to compare diamonds using consistent criteria.