A diamond's clarity refers to its relative freedom from imperfections –. Internal inclusions and / or surface blemishes. Flawless diamonds are absolutely clear. they're the most sought after and consequentially, the most expensive.
However, few things in nature are absolutely perfect. Diamonds are no exception. Most diamonds have internal features, called inclusions. Surface irregularities, called blemishes. Together, they're the diamond's 'clarity characteristics'.
Clarity is the relative absence of these clarity characteristics.
Blemishes are surface imperfections including scratches and nicks. Inclusions are internal, though some might break the surface. Tiny diamond or other mineral crystals may be trapped within the diamond as it forms. Depending on their size and location, they may still be there after the diamond has been cut and polished.
How's clarity graded?
Similar to the colour scale, a system for grading clarity has evolved that's generally accepted in the industry. Here's how the GIA clarity grading scale works:
Shows no inclusions or blemishes of any sort under 10x magnification when observed by an experienced grader.
IF Internally Flawless
Has no inclusions when examined by an experienced grader using 10x magnification. Will still have some minor blemishes.
VVS1 and VVS2 Very Very Slightly Included
Contains minute minutes that are difficult even for experienced graders to see under 10x magnification.
VS1 and VS2 Very Slightly Included
Contains minute examples such as small crystals, clouds or feathers, when observed with effort under 10x magnification.
SI1 and SI2 Slightly Included
Contains inclusions (clouds, included crystals, knots, cavities. Feathers) that are noticeable to an experienced grader under 10x magnification.
I1, I2, I3 Included
Contains inclusions (possibly large feathers or large included crystals) that are obvious under 10x magnification and may affect transparency and brilliance.
* Within the SI clarity grade, –. SI3 –. To denote inclusions that are visible to the naked eye. Don't effect transparency and brilliance to a significant degree.
Clarity and Value
Similar to colour, carat weight and cut, clarity of influence on value is directly related to rarity. The better the clarity grade, the more desirable and valuable the diamond.