Torshab Mine Stone

DESCRIPTIVE MODEL OF SIMPLE Sb DEPOSITS
By James D. Bliss and Greta J. Orris
APPROXIMATE SYNONYM Deposits of quartz-stibnite ore (Smirnov and others, 1983).
DESCRIPTION Stibnite veins, pods, and disseminations in or adjacent to brecciated or sheared fault
zones.
GENERAL REFERENCES White (1962), Miller (1973).
GEOLOGICAL ENVIRONMENT
Rock Types One or more of the following lithologies is found associated with over half of the
deposits: limestone, shale (commonly calcareous), sandstone, and quartzite.
Deposits are also
found with a wide variety of other lithologies including slate, rhyolitic flows and tuffs,
argillite, granodiorite, granite, phyllite, siltstone, quartz mica and chloritic schists, gneiss,
quartz porphyry, chert, diabase, conglomerate, andesite, gabbro, diorite, and basalt.
Textures Not diagnostic.
Age Range Known deposits are Paleozoic to Tertiary.
Depositional Environment Faults and shear zones.
Tectonic Setting(s) Any erogenic area.
Associated Deposit Types Stibnite-bearing veins, pods, and disseminations containing base metal
sulfides ± cinnabar + silver + gold ± scheelite that are mined primarily for lead, gold, silver,

zinc, or tungsten; low-sulfide Au-quartz veins; epithermal gold and gold-silver deposits; hot-
springs gold;carbonate-hosted gold;tin-tungsten veins; hot-springs and disseminated mercury,
gold-silver placers; infrequently with polymetallic veins and tungsten skarns.
DEPOSIT DESCRIPTION
Mineralogy Stibnite + quartz ± pyrite ± calcite; minor other sulfides frequently less than 1
percent of deposit and included ± arsenopyrite ± sphalerite ± tetrahedrite ± chalcopyrite ±
scheelite ± free gold; minor minerals only occasionally found include native antimony, marcasite,
calaverite, berthierite, argentite, pyrargyrite, chalcocite, wolframite, richardite, galena,
jamesonite; at least a third (and possibly more) of the deposits contain gold or silver. Uncommon
gangue minerals include chalcedony, opal (usually identified to be ß-cristobalite by X-ray),
siderite, fluorite, barite, and graphite.
Texture/Structure Vein deposits contain stibnite in pods, lenses, kidney forms, pockets (locally);
may be massive or occur as streaks, grains, and bladed aggregates in sheared or brecciated zones
with quartz and calcite. Disseminated deposits contain streaks or grains of stibnite in host rock
with or without stibnite vein deposits.
Alteration Silicification, sericitization, and argillization; minor chloritization;
serpentinization when deposit in mafic, ultramafic rocks.
Ore Controls Fissures and shear zones with breccia usually associated with faults; some
replacement in surrounding lithologies; infrequent open-space filling in porous sediments and
replacement in limestone.
Deposition occurs at shallow to intermediate depth.
Weathering Yellow to reddish kermesite and white cerrantite or stibiconite (Sb oxides) may be
useful in exploration; residual soils directly above deposits are enriched in antimony.
Geochemical Signature Sb ± Fe ± As ± Au ± Ag; Hg ± W ± Pb ± Zn may be useful in specific cases.





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