Diamond’s Basic Properties | Diamond’s Carbon Isometric Crystal
Simply put, diamond is pure carbon that has crystallized in the isometric (cubic) configuration. It is the only single-element gem that exists on this planet. (Carbon — expressed as C in the periodic table.) Elemental carbon occurs only in three natural forms: diamond, graphite, and amorphous carbon. Amorphous carbon occurs as a type of soot produced by partly-burned hydrocarbons, such as kerosene and natural gas.