Bornite - Cu₅FeS₄

Habit: Crystals are rare, when found they are pseudocubic, dodecahedral, rarely octahedral. Copper-red, brown to bronze on fresh surfaces, but tarnishes to iridescent purple, giving it informal names such as "peacock ore"or "purple copper ore". Opaque, Metallic Luster.

Environment: A common and widespread mineral in copper deposits, principally in Hydrothermal veins with minerals such as quartz, chalcopyrite, pyrite and marcasite. Also occurs in dikes, in contact metamorphic deposits, in Pegmatites and basic intrusives.

Etymology: Named for Ignaz von Born (1742-1791), Austrian mineralogist. An important ore of copper