Cubanite

a mineral, a sulfide of iron and copper, Cul’e₂S₃ (theoretical content: 23.4 percent Cu, 41.2 percent Fe, 35.4 percent S). Cubanite crystallizes in the orthorhombic system. It generally forms thin tabular microscopic intergrowths in chalcopyrite—products of decomposition at a temperature of about 300°C. Cubanite is bronze-yellow in color and exhibits a metallic luster. It has a hardness of 3.5 on the mineralogical scale and a density of 4,030–4,169 kg/m³. It is magnetic. Cubanite occurs in copper-nickel sulfide ore deposits (for example, in Sudbury, Canada). It is a rare mineral and does not form large aggregates.