The clarity of a diamond is a quality that is related to its existence and adding beauty to its visual appearance. It is one of the most important property of diamond grading besides carat, color and cut. Inclusions may be crystals of any foreign material or another diamond crystal, or even structural imperfections like cracks that can appear whitish or cloudy. The size, color, number relative location and visibility of any inclusions can affect the clarity of a diamond. Most of the inclusions do not affect a diamonds performance but a large inclusion may affect its inability to scatter light. It may also reduce a diamonds resistance to fracture.



Diamonds that are high clarity grades are usually more valuable and flawless graded diamonds do fetch a highest price. Minor inclusions of blemishes may also be used to identify a diamonds. There are several different types of blemishes and inclusions which may affect a diamonds clarity to certain degrees. The term internal characteristics is being used by the diamond industries instead of inclusions. For any natural diamond, the inclusions are growth crystals that gives each diamond its character and can be counted as a unique fingerprint that is used to identify a particular diamond. The American Gem Society grades these clarity on a number scale between 0 and 10. All grades do reflect the appearance to an experienced grader when viewed from above at 10x magnification. The grader studies the diamond for its internal characteristics and judges them on the basis of clarity, color, size, number, nature or relief. Most noticeable inclusions are used to assess the clarity grade of a diamond to set its value. Less significant inclusions are usually ignored but may be plotted onto a diamond plot chart.

As larger characteristics are usually more noticeable under magnification, so the clarity characteristic size is the first clarity factor which is used to assess a diamond. The second factor being the number of clarity characteristics. Generally the less clarity characteristics the higher clarity grade. This assessment is usually made on the basis how readily they can be seen and not the actual number of characteristics. The third factor is the characteristics position. When the inclusion is directly under the table of the diamond is it easily visible. If it is positioned close to the pavilion, it will reflect multiple times around the diamond giving it a perfect reflection. So reflectors are grades as if each of the reflection was an inclusion. So reflectors have a greater impact on the clarity grade. The nature of the characteristics also acts as a clarity grade as it determines whether it is internal of external. It also determines if the inclusion poses a risk to the diamond as it may cause a break in the crystal structure. Moreover higher clarity grade diamonds do become increasingly rare pieces of gemstones.