Signature Ideal cut: Top 1% of diamond quality - with precise proportions, polish and symmetry - allowing the diamond to reflect even more light than the standard Ideal cut.

Ideal cut: Highest cut grade. Its proportions produce a beautiful balance of fire and sparkle in a diamond.

Very Good cut: Very slightly less measurable fire or sparkle than an ideal cut diamond, at a more affordable price.

Good cut: Quality at a lower price than a very good cut, still producing a beautiful diamond for the budget-minded.

D color: Highest, absolutely "colorless" grade, appreciated best set in platinum or white gold. Exceptionally rare.

E color: A "colorless" grade appreciated best set in platinum or white gold. Traces of color difficult for even trained eye to detect.

F color: A "colorless" grade appreciated best set in platinum or white gold. Faint color detectable by a trained gemologist.

G color: The highest "near-colorless" grade. Color may be detectable when compared to much higher "colorless" grades. Excellent value.

H color: A "near-colorless" grade, color is only noticeable when compared to much higher color grades. Excellent value.

I color: The last of the "near-colorless" grades, color may be only slightly detectable upon close examination. Exceptional value.

J color: Color may be slightly detectable to the unaided eye, particularly in fancy shapes or diamonds over 1-carat.

K-Z color: Color is visibly subtle to distracting. Blue Nile does not carry diamonds of these color grades.

Flawless: No internal or external characteristics. Internally Flawless: May have external blemishes only. Both extremely rare.

VVS1-VVS2: Very, very slightly included. Characteristics miniscule and difficult to see under 10x magnification, even to a trained eye.

VS1-VS2: Very slightly included. Minor inclusions ranging from difficult (VS1) to somewhat easy (VS2) to see at 10x magnification.

SI1-SI2: Slightly included. Inclusions noticeable at 10x. Best value if eye-clean. SI2 inclusions may be detectable to a keen unaided eye.

I1: Included. Diamonds may have minor eye-visible inclusions. Blue Nile offers a limited selection of jewelry with I1 clarity diamonds.

I2-I3: Included. Will likely have more obvious or distracting inclusions. Blue Nile does not carry I2-3 clarity diamonds.