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Diamond Education

The 4Cs of Diamonds

explains the 4Cs of Diamonds - cut, color, clarity, and carat weight - the most important characteristics to understand when making a diamond purchase.


As the largest online diamond retailer, Blue Nile offers the largest collection of the world's finest cut diamonds. Pre-selected for exceptional quality, the cut, color, and clarity of our loose diamonds are evaluated based on a standardized grading scale. Also, each loose diamond is accompanied by a grading report from either GIA, AGSL, or GemEx, independent diamond grading labs with stringent grading and certification guidelines.

Blue Nile Standards Chart

Price Match Guarantee

If you find a comparable GIA-graded diamond at a lower price, we'll review to match the price.

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Diamond Upgrade Program

We offer a lifetime diamond upgrade program on all GIA and AGSL-graded diamonds.

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Conflict Free Diamonds

Blue Nile diamonds are ethically sourced with a zero-tolerance policy for conflict diamonds.

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