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Formula: SbAsS3
Sulphide, antimony- and
arsenic- bearing mineral
Crystal System: Monoclinic
Specific gravity: 3.92 measured, 3.98 calculated on synthetic material
Hardness: 1½ to 2
Streak: Orange-red
Colour: Dark blood-red, tarnishes to green to purple iridescence
Environments
Getchellite is associated with orpiment,
realgar, stibnite,
cinnabar, galkhaite,
laffittite, chabournéite,
christite, lorándite,
marcasite, quartz,
baryte, fluorite and
calcite
(HOM).
Localities
The type localityis the Getchell Mine, Adam Peak, Potosi Mining District, Osgood Mountains, Humboldt County, Nevada,
USA. The geology of the mine consists essentialiy of a narrow steeply dipping fault zone cutting interbedded
shale, argillite and
limestone near a
granodiorite intrusive. Mineralisation is mainly confined to the
sheared rocks in the fault zone and consists principally of quartz,
calcite, realgar,
orpiment, stibnite,
pyrite, marcasite,
cinnabar, baryte,
fluorite, gypsum and very
fine-grained gold.
Getchellite occurs where the ore body is intimatelv associated with abundant
orpiment and realgar and with
lesser amounts of quartz, stibnite
and cinnabar, all of which occur in the fault zone in veins up to eight
inches thick cutting sheared and brecciated country rocks.
Apparently getchellite was one of the first hydrothermal minerals deposited after
quartz, some getchellite and
orpiment were deposited simultaneously or nearlv so,
stibnite was deposited more or less continuously, but in small amounts,
throughout the period of ore deposition, and cinnabar was among the last
of the minerals deposited. It is concluded that quartz, getchellite,
orpiment, realgar,
stibnite and cinnabar are very
closely associated both in time and in space and were probably transported by, and deposited from, the same or very
similar solutions
(AM 50.1817-1826).
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