Natural diamonds are the result of carbon exposed to tremendous heat and pressure deep in the earth. This process can result in a variety of internal characteristics called inclusions, and external characteristics called blemishes.
Evaluating diamond clarity involves determining the number, size, relief, nature, and position of these characteristics, as well as how these affect the overall appearance of the stone. Fewer inclusions translates to a higher value.
The GIA Clarity Scale has 6 categories:
- Flawless (FL): No inclusions and no blemishes visible under 10x magnification
- 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 clearly visible 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.