Diamonds that are absolutely clear are the most sought-after and therefore the most expensive. But many diamonds have inclusions — trace minerals or other tiny characteristics that can detract from the pure beauty of the diamond. GIA, DCLA, GSL and HRD use a detailed system of rules and standards to summarize the number, location, size, and type of inclusions present in a diamond.

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

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

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

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

I1, I2, P1, P2 Diamonds: Included: Inclusions visible