Asbecasite

asbecasite

titanite

anatase

molybdenite

Images

Formula: Ca3TiAs6Be2Si2O20
Arsenite, titanium and beryllium bearing mineral
Crystal System: Hexagonal
Specific gravity: 3.70
Hardness: 6½ to 7
Colour: Yellow, pale yellow
Environments

Metamorphic environments

Localities

At the Monte Cervandone area, Devero Alp, Baceno, Verbano-Cusio-Ossola Province, Piedmont, Italy, asbecasite was one of the first new arsenic species to be found, on the Wannigletscher in 1963; it has since been found throughout the Cervandone area. Most good crystals are less than 1 cm in size, but exceptional deep orange transparent crystals exceeding 2 cm have been found. The bright yellow colour of fresh, transparent asbecasite crystals has often caused them to be mistaken for the more common Alpine species titanite. Rare wulfenite from Cervandone can also be mistaken for asbecasite. Weathered crystals tend to look whitish or greenish yellow and to be cloudy, having lost their original translucency or transparency.
Asbecasite is typically associated with cafarsite and other arsenic minerals, as well as with chlorite, fluorite, magnetite and quartz (MinRec 56.3.297-299).
Asbecasite from the Monte Cervandone Area - Image

At the type locality, the Wanni glacier - Scherbadung area, Binn, Goms, Valais, Switzerland, asbecasite occurs on cleft faces in orthogneiss. Associated minerals include magnetite, hematite, titanite, apatite, anatase, malachite, azurite, tennantite and molybdenite (HOM).
Asbecasite from the Wanni Glacier - Image

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