Avicennite

avicennite

carlinite

parapierrotite

hematite

Images

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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