Image: <bdi><a href="https://www.wikidata.org/wiki/Q126871368" class="extiw" title="d:Q126871368"><span title="photographer from the United States">Darla Sondrol</span></a></bdi> (CC0)
orthorhombiccommonSulfides
Bornite
Cu5FeS4
This 9 cm specimen of bornite displays a coppery red to brown color on fresh surfaces, which readily tarnishes to an iridescent purple, earning it the nickname 'peacock ore'. It typically forms massive aggregates rather than distinct crystals.
Bornite Physical Properties
Mohs Hardness
3Crystal System
orthorhombicLuster
metallicStreak Color
grayish blackCleavage
poor/indistinct on {111}Fracture
conchoidal to unevenSpecific Gravity
5Colors
coppery red, brown, iridescent purpleTransparency
opaqueType Locality
Worldwide, notable localities include Cornwall (England), Butte (Montana, USA), and Messina (South Africa).Mineral Group
SulfidesUses
copper oreAssociated Minerals
chalcopyrite, pyrite, chalcocite, covellite, quartzRarity
commonGeological Context
Bornite is a primary copper ore mineral found in hydrothermal veins, porphyry copper deposits, and sedimentary copper deposits. It often forms at high temperatures and can be a product of both primary mineralization and secondary alteration.
