Diamond Education
The 4Cs of Diamonds
explains the 4Cs of Diamonds - cut, colour, clarity, and carat weight - the most important characteristics to understand when making a diamond purchase.
find your diamond
Quality
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, colour, 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.
| Grade | Not Carried by Blue Nile | Blue Nile Quality |
|---|---|---|
| Cut | Fair and Poor | Good, Very Good, Ideal, and Astor Ideal |
| Colour | L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, and Z | K, J, I, H, G, F, E, and D |
| Clarity | I1, I2, and I3 | SI2, SI1, VS2, VS1, VVS2, VVS1, IF, and FL |