Description
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. Oxidation changes the color, giving the mineral blue, purple, and red hues. Its hardness is 3 and its average density is 5.09. After heating, bornite is magnetic and not radioactive. Bornite is named after the Austrian mineralogist I. von Born (1742-1791). Bornite is often found in pegmatites. It occurs in Arizona, Butte, and Mexico, among other places. Bornite is an important copper ore and often occurs together with the much more common chalcopyrite. It is important for its copper content: approximately 63% by mass is copper.
