Blue Nile Luxembourg will be officially closed on March 15th, 2023

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.

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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.

Print Sample Report

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

A GIA certified diamond is one that has been graded by the Gemmological Institute of America. These GIA-graded diamonds have a unique GIA Diamond grading Report that identifies the gemstone’s specific qualities. GIA Diamond Grading Reports assess a diamond 4Cs along with any characteristics.

A GIA diamond certification can enhance a gem’s value by adding trustworthy ratings of its most important qualities. A GIA diamond certificate is regarded as the gold standard in diamond grading and reporting. GIA diamonds are often regarded as having higher values than non-GIA gemstones because of the transparency in their grading.

At Blue Nile, we have each loose diamond’s GIA report readily available for transparency in the buying process. If you’d like to complete a GIA report check for any of our graded diamonds, you can review its listing on our website or you can search the diamond’s unique report identification number on GIA’s website as well.

Though many diamonds are GIA-graded, not all have the prestigious grading from this institution. At Blue Nile, we offer GIA reports for our loose diamonds and larger stones. Smaller diamonds, such as pavé or stones in halo rings, typically do not have GIA reporting available. Some jewellers do not opt to have their diamonds graded by the GIA so their gems will not have these reports available. We always suggest opting for GIA certified diamonds when purchasing larger or loose diamonds.

To receive a report from the Gemmological Institute of America, a GIA diamond will be inspected by their experts. They analyse many qualities of a diamond including its cut, colour, clarity, carat and any inclusions. They will also assess the diamond’s shape and other qualities of importance. Then, the diamond is given a report that quantifies its qualities. The GIA is an independent organisation regarded as an authority on gemstone grading.

Yes, the GIA offers grading for lab grown diamonds. These reports will include additional information about the lab-made diamond’s growth process such as CVD or HPHT diamonds.

Learn more about diamond documentation

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 or 001-206-336-7905.