Diamonds that are absolutely clear are the most sought-after and therefore the most expensive. But many diamonds have inclusions — scratches, trace minerals or other tiny characteristics that can detract from the pure beauty of the diamond.

FL, IL Flawless, Internally Flawless: No internal or external flaws. Internally Flawless: No internal flaws. Very rare and beautiful diamonds.

VVS1, VVS2 Very, Very Slightly Included: Very difficult to see inclusions under 10x magnification. An excellent quality diamond.

VS1, VS2 Very Slightly Included: Inclusions are not typically visible to the unaided eye. Less expensive than the VVS1 or VVS2 grades.

SI1, SI2 Slightly Included: Inclusions are visible under 10x magnification, and may be visible with the unaided eye. A good diamond value.

I1, I2, I3 Included: Very visible inclusions .