Arsenolite
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 | |
|---|---|
 Arsenolite from the White Caps Mine, Manhattan District, Nye County, Nevada (size: 6.0 x 4.3 x 2.9 cm) | |
| General | |
| Category | Oxide mineral |
| Formula (repeating unit) | As4O6 |
| Strunz classification | 4.CB.50 |
| Crystal system | Cubic |
| Crystal class | Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m) |
| Space group | Fd3m |
| Unit cell | a = 11.074 Å; Z = 16 |
| Identification | |
| Formula mass | 197.841 g/mol |
| Color | White, pale blue, pink to pale yellow if impure |
| Crystal habit | Common as tiny octahedra; aggregates or crusts; botryoidal, stalactitic |
| Cleavage | On {111} |
| Fracture | Conchoidal |
| Mohs scale hardness | 1.5 |
| Luster | Vitreous to silky; may be earthy or dull |
| Streak | white /pale white |
| Diaphaneity | Transparent |
| Specific gravity | 3.87 |
| Optical properties | Isotropic; may be anomalously anisotropic |
| Refractive index | n = 1.755 |
| Other characteristics | Astringent, sweetish taste; toxic |
| References | [1][2][3] |
Arsenolite belongs to the minerals which are highly toxic.[3]
Occurrence
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]
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