If you are interested in a diamond and a certificate is not available for viewing on the site, simply contact a diamond and jewelry consultant at serviceuk@bluenile.co.uk or 0800-1816543.
What is Diamond Certification?
Diamond certification is a process in which trusted experts use a standardized grading system to quantify key qualities of a diamond. This helps diamond shoppers understand how a specific diamond will look, making it easier to purchase the right gemstone without worry.
Independent certification is how you can be sure that you're getting a quality diamond that’s accurately graded without bias. All Blue Nile loose diamonds are analyzed and graded for quality by the Gemmological Institute of America (GIA), one of the most respected and accurate labs in the diamond industry. Additionally, all Astor by Blue Nile™ diamonds are certified for light performance by GemEx, the leader in light measurement.
Understanding Diamond Grading Reports
Diamond grading, also known as diamond certification, helps demystify a diamond’s most important qualities to help buyers make informed decisions. The two main reports issued by the GIA are the Diamond Grading Report and the Diamond Dossier®. And, while similar, there are important distinctions.
- Diamond Grading Report: Many consider this to be the blueprint of a diamond. Starting with the 4Cs of diamonds – cut, clarity, colour, and carat – the report includes precise measurements and shape, as well as a plot or map of the individual diamond inclusions, also known as characteristics. The diamond grading report will also note if the diamond has a girdle inscription, and will describe important characteristics beyond the clarity grade.
- Diamond Dossier®: This dossier offers the same grading information as the Diamond Grading Report, minus the plotted diagram. To prove authenticity, the dossier also includes the laser inscription number on the diamond’s girdle.
Review a sample GIA Report
Ready to explore the grading behind GIA certified diamonds? You can view our sample GIA Diamond Grading Report to familiarize yourself with the look and orientation of GIA diamond reports. You’ll find a GIA grading report on the product page of every loose diamond on our website, but you can also download a sample below. Note the GIA diamond chart including the 4Cs, a plotted diagram and mapping of the stone’s proportions.

Is it important to get a Diamond Grading Report when you buy a diamond?
Your diamond certification is so important, it’s sometimes referred to as the 5th C. Diamonds with a GIA grading report will help you down the road to:
- Confirm the quality of your diamond
- Help to verify ownership for repair or insurance
- Prove useful if you want to resell a diamond
All Blue Nile diamonds include a GIA Diamond Grading Report
Every loose diamond we sell at Blue Nile has been analyzed and graded by the GIA. Since 1931, this non-profit laboratory has ranked among the most respected in the diamond industry, setting the standards for impartial quality review and education.
Keep in Mind: GIA diamond certification helps buyers understand the quality of the diamond they’re purchasing. This kind of third-party diamond certification ensures that you’re getting a quality stone with transparency for the purchase process. For worry-free diamond selection, choose one that comes with a GIA diamond certificate.
How to Use a GIA Diamond Certificate
To verify a diamond's quality before purchase, be sure to review its GIA Diamond Grading Report or Diamond Dossier and the GemEx certificate if you are buying an Astor by Blue Nile™ diamond. It’s also good to know that your purchase of a custom-built ring, pendant or pair of earrings from Blue Nile comes with an appraisal that includes the retail replacement value of the item for insurance purposes.
Do all labs grade diamonds the same way?
Definitely not. While Blue Nile adheres to GIA standards, diamond grading protocols, systems and nomenclature can vary by organisation. Other labs besides the GIA include the American Gem Society (AGS), European Gemmological Laboratory (EGL), International Gemmological Institute (IGI), and Hoge Raad voor Diamont (HRD).
Diamond Certification FAQs
Learn more about diamond documentation
- GIA Diamond Grading Report
- GIA Diamond Dossier®
- GemEx Diamond Light Performance Certificate
- Blue Nile Appraisal