Definition The presence or absence of inclusions within the diamond and blemishes on its surfaces. These slight birthmarks of nature generally do not affect the beauty of a stone, but they almost always affect its price. Truly flawless diamonds are extremely rare and very valuable.
Because of their unique optical properties, diamonds, more than any other gemstone, are capable of producing the maximum amount of brilliance. While minute crystals of diamond or other minerals are contained in almost all diamonds, a diamond that is virtually free of inclusions and surface markings will be judged as flawless. In these diamonds, nothing interferes with the passage of light or spoils the beauty. But these diamonds are extremely rare and will command a high price.
To determine a diamond’s clarity grading, it must be examined under a 10x magnification by a trained, skilled eye. What minute inclusions there may be make every diamond unique. These are, in fact, nature’s fingerprints and do not mar the diamond’s beauty nor endanger its durability. Without high magnification, you may never see these inclusions. However, the fewer there are, the rarer your diamond will be.