Clarity refers to the absence, or presence, of internal characteristics (inclusions) and external characteristics (blemishes) in a diamond.
Diamonds are the result of carbon exposed to tremendous heat and pressure deep in the earth. Small crystals can become trapped in a diamond when it’s forming, and as a crystal grows, it can develop irregularities in its atomic structure. This causes characteristics to form in the diamond.
Evaluation involves determining the number, size, relief, nature, and position of these characteristics and how they affect the overall appearance of the diamond.
No diamond is perfectly pure, but the fewer inclusions and blemishes, the better its clarity.
There are 6 categories, some of which are divided, for a total of 11 grades.
- 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 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
Many inclusions and blemishes are so tiny, they can’t be seen without magnification and a trained eye.
Examples of inclusions in various stones: