Images
Formula: Ag3AsS3
Sulpharsenite,
proustite group,
paramorph of
xanthoconite,
above 300oC forms a series with pyrargyrite
(AM 48.725-736)
Crystal System: Trigonal
Specific gravity: 5.57 measured, 5.625 calculated
Hardness: 2½；
Streak: Scarlet red
Colour: Red
Solubility: Slightly soluble in nitric acid
Common impurities: Sb
Environments:
Proustite is a late-forming mineral in hydrothermal deposits, in the oxidised and enriched zone, associated with
other silver minerals
and sulphides. Associated minerals include silver, arsenic,
xanthoconite, stephanite,
acanthite, tetrahedrite and
chlorargyrite
(HOM).
Localities
the type locality is Jáchymov, Karlovy Vary District, Karlovy Vary Region, Czech Republic.
Proustite from Jáchymov - Image
At Johanngeorgenstadt, Erzgebirgskreis, Saxony, Germany, during the heyday of mining at Johanngeorgenstadt,
proustite was found fairly abundantly in the cementation zones and the upper
primary zones in many
silver ore veins, but proustite in lesser quantity and of inferior
quality was also met with in deeper-lying parts of the deposit, in the bismuth
- cobalt - nickel ore veins. The largest
and most attractive crystals, some to several centimeters long, were found abundantly in the Gnade Gottes and
Neujahr Maassen mines. In the early days, proustite-pyrargyrite
(there was often little distinction made) was commonly encountered in other mines of the district as well. Associated
minerals included marcasite,
acanthite, native silver,
native arsenic, cobalt -
nickel ores, native bismuth,
galena, sphalerite,
quartz and dolomite. During the
1945–1958 mining period, proustite was found again, chiefly as pyramidal crystals in the
bismuth - cobalt -
nickel - silver ore veins; associations
there included native arsenic, galena,
sphalerite and cobalt -
nickel ores
(MinRec 55.5.616-616).
Proustite from Johanngeorgenstadt - Image
At the Imiter mine, Imiter District, Tinghir Province, Drâa-Tafilalet Region, Morocco, proustite is abundant as small crystals in
lead-rich quartz masses; less commonly it is found in black
shale, and very rarely in dolomite cavities.
Associated minerals include galena, quartz,
xanthoconite, polybasite -
pearceite, native silver and, less abundantly,
imiterite
(Minrec 42-2.127-128).
Proustite from Imiter - Image
At Tamdrost, Zagora Province, Drâa-Tafilalet Region, Morocco, proustite occurs in calcite veins
as crystals to 4 mm with löllingite and native silver
(Minrec 38.5.388).
At the Uchucchacua mine, Oyon Province, Lima, Peru, proustite crystals to 1 cm have been found on
pearceite crystals
(Minrec 42.2.156).
Proustite from Uchucchacua - Image
Back to Minerals