Friedrichite

friedrichite

cuprobismutite

covellite

tetradymite

Images

Formula: Cu5Pb5Bi7S18
Sulphosalt, bismuth-bearing mineral, a member of the aikinite-bismuthinite series
Specific gravity: 6.98
Hardness: 3½ to 4
Colour: Silver-grey
Environments

Metamorphic environments

Localities

At the type locality, Sedl, Nasenkopf mountain, Bramberg am Wildkogel, Zell am See District, Salzburg, Austria, friedrichite occurs as aggregates of granular-shaped crystals, associated with chalcopyrite, covellite, chlorite and mica, in vein quartz boulders (CM 16.127-130).

At the Băiţa mining district, Nucet, Bihor, Romania, granodioritic intrusions are thought to be responsible for the copper-bismuth- molybdenum-tungsten mineralisation. The ores are generally emplaced within skarns developed along the contacts of the intruded rocks with the plutons. In the Antoniu magnesian skarn deposit, the bismuth-copper- tungsten mineralisation is developed within recrystallised dolostone. The most common skarn is a clinopyroxene skarn with a diopside-dominant core passing to a narrow zone that includes chondrodite, clinohumite and phlogopite. The other constituents of the diopside-rich core include kotoite, fluoborite and szaibelyite. The principal ore minerals are chalcopyrite, aikinite, bismuth, wittichenite, cuprobismutite, cupropavonite, cosalite, tetradymite, sphalerite, galena, bornite, molybdenite and scheelite. Cuprobismutite and tetradymite appear in direct association with friedrichite. In the upper part of the ore deposit, weathering has led to the formation of copper, cuprite, bismuth, malachite and azurite.
The Blidar Secundar contact skarn deposits contain molybdenum-bismuth- tungsten mineralisation. Ores occur as veinlets mainly composed of wollastonite, grossular-andradite, diopside-hedenbergite and vesuvianite. The principal ore minerals in these two deposits are bismuthinite, molybdenite, scheelite, magnetite, hematite, pyrite, chalcopyrite, sphalerite, galena, galenobismutite, cosalite, aikinite, hammarite, gladite, pekoite, padĕraite, kobellite, emplectite, cuprobismutite, wittichenite, tetrahedrite, cupropavonite, tetradymite, altaite, joséite-A, bismuth and gold (CM 36.861-868).

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