Clarity is the term used to describe the size and number of inclusions in a diamond. Almost all diamonds contain minute traces of non-crystallized carbon, the element from which they were born, and growth marks.
These inclusions are nature's finger print and make every diamond quite unique. Most are not discernible to the naked eye and require magnification to become apparent.
Large inclusions interfere with the dispersion of light and therefore the diamond's brilliance. The larger or more numerous the inclusions the less valuable the diamond. The fewer the inclusions, the rarer the stone. In short Clarity is how "clean and clear" the diamond is. To grade the clarity of a diamond, a 10x magnification is used to inspect the diamonds for inclusions.
After inspections one of the following grade is assigned:

FL or IF A diamond that shown no inclusions and external blemishes under a 10x magnifications will be graded as Flawless. If there are only some polish marks visible (an external blemishes) the diamond will be graded as Internal Flawless. Diamonds that are graded FL or IF are considered extremely rare. Close	: Flawless or Internal Flawless A diamond that shown no inclusions and external blemishes under a 10x magnifications will be graded as Flawless. If there are only some polish marks visible (an external blemishes) the diamond will be graded as Internal Flawless. Diamonds that are graded FL or IF are considered extremely rare. Close
VVS1 or VVS2 Or Very Very Slightly Included. Under a 10x magnification inclusions are very difficult to see for a trained grader, the diamond will usually only has minute pinpoints. VVS graded diamonds are very rare. Close	: Very Very Small inclusions Or Very Very Slightly Included. Under a 10x magnification inclusions are very difficult to see for a trained grader, the diamond will usually only has minute pinpoints. VVS graded diamonds are very rare. Close
VS1 or VS2 Or Very Slightly Inclusions. The diamond will have minor inclusions and are still difficult to see for the untrained eye. Close	: Very Small inclusions Or Very Slightly Inclusions. The diamond will have minor inclusions and are still difficult to see for the untrained eye. Close
SI1 or SI2 Or Slightly Included. Inclusions will be easy to see with 10x magnification. Most of the time the inclusions will not be visible with the unaided eye. SI1 and SI2 graded diamonds are the best when it is about price/quality. Close	: Small Inclusions Or Slightly Included. Inclusions will be easy to see with 10x magnification. Most of the time the inclusions will not be visible with the unaided eye. SI1 and SI2 graded diamonds are the best when it is about price/quality. Close
I1, I2 or I3 Or Included. Diamonds with an I grading have inclusions that are obvious when viewed under 10x magnification. The inclusions are even visible to the trained naked eye. Close	: Inclusions Or Included. Diamonds with an I grading have inclusions that are obvious when viewed under 10x magnification. The inclusions are even visible to the trained naked eye. Close

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