Arsenolite

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Arsenolite
Arsenolite-333170.jpg
Arsenolite from the White Caps Mine, Manhattan District, Nye County, Nevada (size: 6.0 x 4.3 x 2.9 cm)
General
CategoryOxide mineral
Formula
(repeating unit)
As4O6
Strunz classification4.CB.50
Crystal systemCubic
Crystal classHexoctahedral (m3m)
H-M symbol: (4/m 3 2/m)
Space groupFd3m
Unit cella = 11.074 Å; Z = 16
Identification
Formula mass197.841 g/mol
ColorWhite, pale blue, pink to pale yellow if impure
Crystal habitCommon as tiny octahedra; aggregates or crusts; botryoidal, stalactitic
CleavageOn {111}
FractureConchoidal
Mohs scale hardness1.5
LusterVitreous to silky; may be earthy or dull
Streakwhite /pale white
DiaphaneityTransparent
Specific gravity3.87
Optical propertiesIsotropic; may be anomalously anisotropic
Refractive indexn = 1.755
Other characteristicsAstringent, sweetish taste; toxic
References[1][2][3]

Arsenolite is an arsenic mineral, chemical formula As4O6. It is formed as an oxidation product of arsenic sulfides. Commonly found as small octahedra it is white, but impurities of realgar or orpiment may give it a pink or yellow hue. It can be associated with its dimorph claudetite (a monoclinic form of As2O3) as well as realgar (As4S4), orpiment (As2S3) and erythrite, Co3(AsO4)2·8H2O.[1]

Arsenolite belongs to the minerals which are highly toxic.[3]

Occurrence[edit]

It was first described in 1854 for an occurrence in the St Andreasberg District, Harz Mountains, Lower Saxony, Germany.[3]

It occurs by the oxidation of arsenic-bearing sulfides in hydrothermal veins. It also occurs as a result of mine or coal seam fires.[1]

References[edit]