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Formula: PbBiCu6O4(SeO3)4(OH).H2O
Selenite, bismuth-bearing mineral
Crystal System: Tetragonal
Specific gravity: 4.851 calculated
Hardness: 3
Colour: Green
Common impurities: Ca
Environments
Sedimentary environments
Hydrothermal environments
Favreauite is a relatively new mineral, approved in 2014 and to date (May 2023)
reported only from the type locality. It is a secondary mineral
formed by the oxidation of a selenide-bearing hydrothermal vein hosted by
sandstones and shales
(HOM).
Localities
At the type locality, El Dragón mine, Porco Municipality, Antonio Quijarro Province, Potosí, Bolivia, favreauite
is a secondary
selenite mineral that occurs in vughs in a matrix of
cobalt- and copper- rich
penroseite, dolomite and
goethite. Associated minerals include
ahlfeldite, allophane,
alfredopetrovite, calcite,
chalcomenite,
malachite and molybdomenite.
Favreauite forms tiny green square tabular crystals, up to 0.1 mm on edge and 0.01 mm thick, occurring in
subparallel and divergent groups
(EJM 26.771-781, HOM).
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