Diamond clarity is the assessment of small imperfections on the surface and within the stone. The highest grades are FL-IF, which means Flawless/Internally Flawless. The grading scale determines how many inclusions (air bubbles, cracks, etc.) and blemishes a diamond contains.
Typical range for Clarity is SI1 to VVS1.
Clarity is one of the most important characteristics of a diamond. It is the quality of diamonds relating to the existence and visual appearance of internal characteristics of a diamond called inclusions, and surface defects called blemishes.
Basically there are two types of flaws: inclusions and blemishes. Inclusions refer to internal flaws and blemishes refer to surface flaws. Inclusions include flaws such as air bubbles, cracks, and non-diamond minerals found in the diamond. Blemishes include scratches, pits, and chips. Diamonds with no or few inclusions and blemishes are more valuable than those with less clarity.
A clarity grade is assigned based on the overall appearance of the stone under ten times magnification.
F - Flawless: No Internal or External Flaws. Extremely Rare.
IF - Internally Flawless: no Internal Flaws, but some Surface Flaws. Very Rare.
VVS1-VVS2 - Very Very Slightly Included (Two Grades): Minute Inclusions Very Difficult to Detect under 10x Magnification by a Trained Gemologist.
VS1-VS2 - Very Slightly Included (Two Grades): Minute Inclusions Seen only with Difficulty under 10x Magnification.
SI1-SI2 - Slightly Included (Two Grades): Minute Inclusions more Easily Detected Under 10x Magnification.
I1-I2-I3 - Included (Three Grades): Inclusions Visible under 10x Magnification As Well As to the Human Eye.