Diamond cleavage is a straight-lined crack in a cut diamond. Diamond cleavage is one of many inclusions, or flaws, that reduce the value of a diamond. Diamond cleavage reduces the value of diamonds not only because it is a cosmetic flaw, but also because cleavage can eventually lead to a break in the diamond.
There are two types of diamond cleavage: feather-like cleavage and cleavage fissures. Gemnation offers images of both types of inclusions and many other common diamond inclusions. Most diamonds contain inclusions, since there are not many perfect diamonds in the world, and those that are perfect are extremely expensive. However, most diamond inclusions do not have much effect on the appearance or strength of the diamond.
Additionally, the inclusions of a diamond are what make it unique and identifiable if lost or stolen. Diamond cleavage is one of many inclusions, or flaws, that may reduce the value of a diamond if too pronounced. Clouds are small impurities or voids that look like dust particles in the diamond. Bearding is another inclusion that looks like little hairs along the girdle of the diamond. Another inclusion happens when minerals or crystals, such as other diamond or garnet crystals, are trapped inside a diamond.