Diamond clarity refers to absence of inclusions and blemishes. Surface flaws are called blemishes, while defects are known as inclusions. In most cases, a diamond’s beauty is not affected by these in any way since most inclusions can’t be seen with the naked eye. When referring to inclusions, gemologists often use the term “internal characteristics” instead of flaws. Internal characteristics are what give a natural diamond its character.
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. If you are trying to determine what is the best for a diamond, remember that no diamond is perfectly pure. But the closer it comes to purity, the better its clarity.
The GIA Diamond Clarity Scale has 6 categories, some of which are divided, for a total of 11 specific 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 too tiny to be seen by anyone other than a trained diamond grader. To the naked eye, a VS1 and an SI2 diamond may look exactly the same, but these diamonds are quite different in terms of overall quality.