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Formula: Cu6(Cu4Zn2)Bi4S12S
Sulphide, annivite subgroup,
tetrahedrite group,
copper-, zinc- and
bismuth- bearing mineral
Crystal system: Isometric
Specific gravity: 5.259 calculated for the empirical formula
Hardness: 4
Streak: Grey
Colour: Dark grey
Environments
Metamorphic environments
Hydrothermal environments
Localities
At the Maurizi Mine (Mauritius Mine), Hřebečná, Abertamy, Karlovy Vary District, Karlovy Vary Region, Czech
Republic, annivite-(Zn) has been identified during the investigation of samples from dump material of the
abandoned tin mine. The mineralisation studied, in coarse-grained quartz
gangue with abundant
fluorapatite, differs significantly from the usual fine-grained
greisens mined in this area. Annivite-(Zn) was determined in
one sample as anhedral domains 5 to 20 μm in size enclosed in grains of
bismuth-rich
tennantite-(Zn) in close association with
arsenopyrite and pyrite.
Other associated primary minerals are
chalcopyrite, sphalerite,
copper sulphides (anilite,
digenite, geerite,
spionkopite and covellite),
aikinite, bismuthinite,
berryite, cuprobismutite,
emplectite and wittichenite
(MM 89.1.102-112).
At the type locality, the Geister vein, Rovnost Mine, Jáchymov, Karlovy Vary District, Karlovy Vary Region, Czech
Republic, the type sample of annivite-(Zn), originally labelled "walpurgite", (6 × 4 cm) is formed of a
massive aggregate of ore composed of tetrahedrite group
minerals, emplectite and
bismuth, and is partly
supergene altered
(bismite and walpurgite). The
predominant mineral of the tetrahedrite group is
bismuth-rich
tennantite-(Zn) accompanied by annivite-(Zn) and more rarely
also bismuth-rich
tennantite-(Fe).
Annivite-(Zn) was also identified in other samples from the Geister vein. The mineral association includes,
in addition to annivite-(Zn), bismuth-rich
tennantite-(Zn),
tennantite-(Fe),
tetrahedrite-(Zn), the not-yet approved ‘annivite-(Fe)’,
bismuth, emplectite,
wittichenite and
supergene bismite,
walpurgite, arsenates of the
vivianite group and
metazeunerite. The
tetrahedrite group minerals form strongly chemically zoned
aggregates and annivite-(Zn) occurs only as tiny growth zones and isometric domains.
In holotype material, annivite-(Zn) occurs as anhedral grains, up to 50 μm in size, and growth zones (up to
100 μm in thickness) in zoned annivite-(Zn)/tennantite-(Zn)
grains. It is dark grey in colour, with a grey streak and metallic lustre. Annivite-(Zn) is brittle, with a
conchoidal fracture and indistinct cleavage
(MM 89.1.102-112).
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