Getchellite

getchellite

galkhaite

christite

lorandite

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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

Hydrothermal 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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