21 Photos
Bornite
Chemical Formula	Cu5FeS4
Species	Sulfides
Crystal System	Orthorhombic
Mohs Scale	3
Specific Gravity	4.9-5.3
Color	Copper red, bronze brown, purple
Streak	grayish black
Luster	Metallic
Refractive Index	Opaque
Diaphaneity	Opaque
Cleavage	Poor/IndistinctIn traces on .
Fracture	Irregular/Uneven
Crystal Habit：Granular, massive, disseminated - Crystals pseudocubic, dodecahedral, octahedral
Geological Setting：Common and widespread in copper ore deposits. It also occurs in basic intrusives, in dikes, in contact metamorphic deposits, in quartz veins and in pegmatites.

Bornite, also known as Peacock ore, is a sulfide mineral with chemical composition Cu₅FeS₄ that crystallizes in the orthorhombic system (pseudo-cubic).

Appearance

Bornite has a brown to copper-red color on fresh surfaces that tarnishes to various iridescent shades of blue to purple in places. Its striking iridescence gives it the nickname peacock copper or peacock ore.

Mineralogy

Bornite is an important copper ore mineral and occurs widely in porphyry copper deposits along with the more common chalcopyrite. Chalcopyrite and bornite are both typically replaced by chalcocite and covellite in the supergene enrichment zone of copper deposits. Bornite is also found as disseminations in mafic igneous rocks, in contact metamorphic skarn deposits, in pegmatites and in sedimentary cupriferous shales. It is important as an ore for its copper content of about 63 percent by mass.

Occurrence

It occurs globally in copper ores with notable crystal localities in Butte, Montana and at Bristol, Connecticut in the U. S. It is also collected from the Carn Brea mine, Illogan, and elsewhere in Cornwall, England. Large crystals are found from the Frossnitz Alps, eastern Tirol, Austria; the Mangula mine, Lomagundi district, Zimbabwe; from the N’ouva mine, Talate, Morocco, the West Coast of Tasmania and in Dzhezkazgan, Kazakhstan.

History and etymology

It was first described in 1725 for an occurrence in the Kru?né Hory Mountains (Erzgebirge), Karlovy Vary Region, Bohemia in what is now the Czech Republic. It was named in 1845 for Austrian mineralogist Ignaz von Born (1742–1791).