Excellent deep lustrous brown lenticular crystals of Siderite with a petal-like appearance, from the Illogan mining area of Cornwall. Probably the most intensively mined area of the Duchy of Cornwall. The crystals of Siderite measuring to 0.6cm are densely clustered over milky white prismatic terminated Quartz crystals, with inter grown brassy yellow crystals of Chalcopyrite. The matrix is a Quartz grey-green Chlorite inter mixed with areas of Chalcopyrite. A specimen with well developed Siderite crystals.