Surface irregularities and the amount of internal inclusions determine a diamond's clarity. In order to determine clarity, an expert views the diamond under a magnification of 10x. The fewer internal inclusions and surface irregularities a diamond has the higher clarity rating it will receive.  Location, size, type and color of internal and external inclusions also affect grading and value.

A higher clarity indicates a more rare and valuable diamond. However, higher clarity does not necessarily mean a more beautiful diamond because many inclusions and surface irregularities are not visible to the human eye. At a clarity level of SI2, inclusions and surface irregularities cannot be seen by the average naked eye. Diamonds with a clarity rating higher than SI2 are sought after more for their rarity than for their increase in beauty.