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Formula: Ag6(Ag4Fe2)As4S13
Valence: Ag1+6(Ag1+4Fe2+2)As3+4S2-13
Sulpharsenite,
zvěstovite subgroup,
tetrahedrite group,
silver-bearing mineral
Crystal system: Isometric
Specific gravity: 5.043 calculated
Hardness: 3 to 3½
Streak: Black
Colour: Iron-black, with ubiquitous and deep red internal reflections
Environments
Carbonatites
Hydrothermal environments
Zvestovite-(Fe) is a new mineral, approved in 2022.
Localities
At the type locality, the Ulatayskoe Ag-Cu-Co occurrence, Ovyursky District, Tuva, Russia, zvestovite-(Fe) occurs
as anhedral grains, up to 1 × 0.4 mm in size but usually much smaller, closely intergrown with
native silver, in Mg-bearing
siderite–quartz
gangue in ore-bearing siderite
carbonatites and formed by the circulation of
low-temperature hydrothermal fluids. Associated minerals include acanthite,
chlorargyrite, cobaltite,
gersdorffite, jalpaite,
kenoargentotennantite-(Fe),
krutovite, löllingite,
malachite, muscovite,
pearceite, quartz,
safflorite, siderite,
native silver, skutterudite,
tennantite-(Zn) and
zvěstovite-(Zn)
(Mindat).
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