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Formula: CaSb3+4O4(SO4)2(OH)2.2H2O
Sulphate, antimony-bearing mineral
Crystal system: Monoclinic
Specific gravity: 4.06 calculated for the ideal formula
Hardness: 3½ to 4
Colour: Colourless, can be pink due to encrustations of valentinite
Environments
Sedimentary environments
Hydrothermal environments
Peretaite is a rare mineral, formed by the action of sulphuric acid solutions on
stibnite in the oxidised zone of a
limestone-hosted hydrothermal
antimony-bearing deposit. Associated minerals include
stibnite, pyrite,
kermesite, sulphur,
valentinite, onoratoite,
klebelsbergite, gypsum,
calcite and quartz
(HOM).
Localities
At the type locality, the Pereta Mine, Scansano, Grosseto Province, Tuscany, Italy, peretaite occurs, in
small quantities, as aggregates of tabular crystals in the geodes of a deeply silicified
limestone, and also in the cavities of columnar
stibnite. Crystals of peretaite are associated with acicular
crystals of klebelsbergite,
stibnite, quartz,
calcite, pyrite,
valentinite, kermesite,
sulphur and gypsum. Aggregates
of klebelsbergite crystals and rarely of peretaite are often
red from incrustations of valentinite. Unlike
klebelsbergite, which was found rather abundantly in the
fissures of the stibnite veinlets, peretaite occurs closer to
the boundary with limestones. Peretaite, as well as
klebelsbergite, has apparently been formed by the action of
sulphuric acid on stibnite; the source of the calcium in
peretaite is likely the limestone of the countrv rock
(AM 65.936-939).
Peretaite from the Pereta Mine -
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