Crystals of metallic grey Bournonite are scattered over the polymetallic specimen from the Trepca orebody complex, Kosovo. Crystals of Bournonite display the cogwheel repeat twinning habit to advantage, crystals measuring to 1.3cm, on a mixed sulphides matrix of tabular crystals of Pyrrhotite completely replaced by light metallic yellow Pyrite, with later Galena and Sphalerite, and areas of white-red Calcite.