This chalcotrychite crystals are from the Daye Copper Mine in the Huangshi Prefecture, Hubei Province, China. This is an iron and copper mine that contains over 25 types of minerals including chalcotrychite. It is a copper oxide, elements Cu and O, that is a variable form of cuprite. This specimen consists of a thick gossan matrix that is partially covered, on the display side, with a thin layer of limonite and mats of fibrous chalcotrichite crystals. The crystals have a magenta to red color and a sub-metallic luster. This piece measures 2 1/2 x 2 inches or 64 x 50 mm on the display surface. The matrix is 1 1/2 inches or 38 mm thick.