The clarity of a diamond is measured via the Diamond Clarity Chart. Below are grades and categories of diamond rings:
Flawless (FL) Diamond Rings
Flawless diamond earrings have no inclusions or blemishes under 10Xs magnfication
Internally Flawless (IF) Diamond Rings
Internally flawless diamond rings have no inclusions under 10Xs magnification, but small blemishes exist on the diamond surface.
Very Very Slightly Included (VVSI) Diamond Rings
VVSI diamond rings can be further categorized into VVS1 and VVS2. The diamonds have very small inclusions under 10Xs magnification. VVS1 has slightly better clarity then VVS2.
Very Slightly Included (VSI) Diamond Rings
VSI diamond rings have small inclusions. VSI diamond rings are sub categorized as VS1 and VS2. VS2 diamond rings can show inclusions to the naked eye.
Included Diamond Rings
Inclusions can be often be seen by the naked eye. Included diamond rings can be separated into I1, I2, & I3, with I1 being the clearest.