Chalcopyrite also Bornite (peacock feather or peacock eye) 6-10 cm

The mineral bornite is a copper-iron sulfide with the chemical formula Cu5FeS4. The mineral has an orthorhombic crystal structure. It has a brown to copper red color on a fresh fracture surface. Oxidation changes the color and gives the mineral blue, purple and red hues. The hardness is 3 and the average density is 5.09. When heated, bornite is magnetic and it is not radioactive. Bornite is named after the Austrian mineralogist I. von Born (1742-1791). Bornite is commonly found in pegmatites. It occurs in Arizona, Butte and Mexico, among others. Bornite is an important copper ore and often co-occurs with the much more common chalcopyrite. It is important for the amount of copper it contains: about 63 percent by mass is copper.