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Formula: Cu5Pb5Bi7S18
Sulphosalt, bismuth-bearing mineral, a member of the
aikinite-bismuthinite series
Crystal System: Orthorhombic
Specific gravity: 6.98 measured. 7.06 calculated
Hardness: 3½ to 4
Colour: Silver-grey
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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