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Formula: Tl2O3
Simple oxide of thallium
Crystal System: Isometric
Specific gravity: 8.9 measured, 10.34 calculated
Hardness: 1½ to 2½
Streak: Greyish black, black with a brownish tint
Colour: Greyish black with brownish black tint
Solubility: Dissolves with difficulty in concentrated acids
Common impurities: Fe
Environments
Sedimentary environments
Hydrothermal environments
Localities
At Vizzaron de Marques, Cadereyta Municipality, Queretaro, Mexico, avicennite occurs as a coating on
quartz and hematite
(Dana).
At the type locality, Dzhuzumli village, Zirabulak Mountain, Samarqand, Uzbekistan, avicennite occurs as
greyish black crystals less than 1 mm in size, somewhat resembling
perovskite. It occurs in the weathered zone of a
hematite-calcite vein cutting
banded marmorised (metamorphosed into marble) and silicified
limestone near its contact with
granite-gneiss. The
veins contain coarsely crystalline limestone, densely impregnated
with iron oxides, iron-rich clay and
hematite
(AM 44.1324-1325).
At the Carlin Gold mine, Elko, Lynn Mining District, Eureka County, Nevada, USA, avicennite is formed by
oxidation of carlinite in carbonaceous
gold ores in silicified
limestone and quartz.
Associated minerals include carlinite,
hematite and quartz
(HOM).
At Lookout Pass Thallium prospect, Little Valley, Lookout Pass Mining District, Tooele County, Utah, USA,
avicennite is associated with parapierrotite
(HOM).
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