Alarsite

Alarsite (AlAsO4) is an aluminium arsenate mineral with its name derived from its composition: aluminium and arsenate.[1] It occurs as brittle subhedral grains which exhibit trigonal symmetry. It has a Mohs hardness of 5-5.5 and a specific gravity of 3.32. It is semitransparent, colorless with pale yellow tints and shows a vitreous luster. It is optically uniaxial (+) with refractive indices of nω = 1.596 and nε = 1.608.

Alarsite
Alarsite.jpg
Alarsite crystals found at Tolbachik
General
CategoryMineral
Crystal systemtrigonal
Crystal classaluminium arsenate
Space groupP3121 (no. 152) or P3221 (no. 154)
Identification
Colourcolorless with pale yellow tints
Mohs scale hardness5-5.5
Lustervitreous luster
Specific gravity3.32.
Refractive indexnω = 1.596 and nε = 1.608.

It was reported from fumaroles in the Tolbachik volcano, Kamchatka, Far Eastern Region, Russia.[2][3] It occurs in association with fedotovite, klyuchevskite, lammerite, nabokoite, atlasovite, langbeinite, hematite and tenorite.[1]

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