Black jade is a nephrite that contains graphite. Its colour ranges from inky black to light black depending on the amount and pattern of the graphite. Its colour is often cloudy or striped, and it can be labelled as dark cloud-like, light ink-like, marten beard-like or belle beard-like. On a single piece of jade, the intensity and distribution of the black can vary, and so it can be further divided into ‘all black’, ‘clustered black’ and ‘dotted black’. Clustered black refers to clustering of graphite in white or green nephrite, and it can be crafted to become a complementary colour or feature on the stone. However, dotted black stones are difficult to craft due to the scattered pattern. The all black type with a moistened appearance can be used as high-grade gemstone.