A diamond’s clarity is measured by the existence or absence of visible flaws. Tiny surface blemishes or internal inclusions, even those seen only under magnification, can alter the brilliance of the diamond and thus affect its value. Clarity levels begin with flawless (FL, IF), followed by very, very slight (VVS1, VVS2), very slight (VS1, VS2), slightly included (SI1, SI2), and included (I1, I2, and I3).
Flawless (FL): No inclusions and no blemishes visible under 10x magnification, very rare.
Internally Flawless (IF): No inclusions visible under 10x magnification.
Very, Very Slightly Included (VVS1 and VVS2): Inclusions so slight they are difficult for a skilled grader to see under 10x magnification.
Very Slightly Included (VS1 and VS2): Inclusions are observed with effort under 10x magnification, but can be characterized as minor.
Slightly Included (SI1 and SI2): Inclusions are noticeable under 10x magnification.
Included (I1, I2, and I3): Inclusions are obvious under 10x magnification which may affect transparency and brilliance.