Chemistry:Cafarsite
From HandWiki
Short description: Rare calcium iron arsenite mineral
| Cafarsite | |
|---|---|
 Cafarsite on granite | |
| General | |
| Category | Arsenites |
| Formula (repeating unit) | Ca8(Ti,Fe2+,Fe3+,Mn)6–7(AsO3)12·4H2O |
| Strunz classification | 4.JC.05 |
| Crystal system | Isometric |
| Crystal class | Diploidal (m3) H–M Symbol (2/m 3) |
| Space group | Pn3 |
| Unit cell | a = 15.984 Å; Z = 4 |
| Identification | |
| Formula mass | 2,230.31 g/mol |
| Color | Dark brown |
| Crystal habit | Cubic/octahedral crystals |
| Fracture | Conchoidal |
| Mohs scale hardness | 5 1⁄2 - 6 |
| |re|er}} | sub-metallic |
| Streak | Yellow brown |
| Diaphaneity | Translucent to opaque |
| Specific gravity | 3.9 |
| Optical properties | Isotropic |
| Refractive index | n = 2.2 |
| References | [1][2][3] |
Cafarsite (Ca8(Ti,Fe2+,Fe3+,Mn)6–7(AsO3)12·4H2O) is a rare calcium iron arsenite mineral. Manganese and titanium occur with iron in the formula.
It was first described in 1966 for an occurrence in the Binn Valley, Valais, Switzerland . Its name is from the composition, calcium, ferrum (iron), and arsenic.[2][1][3] It has also been reported from Piedmont, Italy and the Hemlo gold mine in the Thunder Bay District, Ontario, Canada.[3][2]
References
- ↑ 1.0 1.1 Cafarsite Mineral Data from Webmineral
- ↑ 2.0 2.1 2.2 Cafarsite on Mindat.org
- ↑ 3.0 3.1 3.2 Handbook of Mineralogy
- ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode: 2021MinM...85..291W.
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