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Formula: CoAsS
Valence: Co3+(AsS)3-
Sulpharsenide of cobalt,
löllingite group
Crystal system: Monoclinic
Specific gravity: 5.95 measured, 6.188 calculated
Hardness: 5
Streak: Nearly black
Colour: Steel-grey to silver
Common impurities: Fe3+, Ni
Environments
Metamorphic environments
Hydrothermal environments
Alloclasite occurs in calcite or
quartz veins of apparently low-temperature, late-stage hydrothermal origin,
and also in silicified, recrystallised metamorphic rock. Associated minerals include
gold, silver,
glaucodot, cobaltite,
danaite, emplectite,
bismuthinite, sphalerite,
calcite and quartz
(HOM).
Localities
The type locality is Elizabeth Mine, Oraviţa, Caraş-Severin County, Romania.
Alloclasite from Elizabeth Mine -
Image
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