Very characteristic specimen of Chalcopyrite and Hematite on Siderite from the Carn Brea Mine, Illogan, Cornwall. Brassy yellow well formed crystals of Chalcopyrite measuring to 8mm, are seen as inter grown clusters, associated with metallic black platy crystals of Hematite. Biscuit coloured inter grown lenticular crystals of Siderite forms the matrix for the two minerals.