Schmiederite is a secondary mineral in the oxidized zone of selenium-bearing hydrothermal base metal deposits. Its chemical formula is Pb2Cu2(Se4+O3)(Se6+O4)(OH)4.[3][4]
| Schmiederite | |
|---|---|
 | |
| General | |
| Category | Selenate minerals |
| Formula (repeating unit) | Pb2Cu2(Se4+ O 3)(Se6+ O 4)(OH)4 |
| IMA symbol | Scm[1] |
| Strunz classification | 7.BC.65 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | P21/m |
| Unit cell | a = 9.92 Å, b = 5.71 Å c = 9.36 Å; β = 101.86°; Z = 2 |
| Identification | |
| Color | Pale to deep Prussian blue |
| Crystal habit | Fibrous in radial clusters; may be in crusts; powdery |
| Luster | Subadamantine to satiny |
| Streak | Light blue |
| Diaphaneity | Transparent |
| Specific gravity | 5.62 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.85–1.9 nβ = 1.9–1.95 nγ = 1.95–2.1 |
| References | [2][3][4] |
It was first described in 1962 for an occurrence in the Cóndor mine, Los Llantenes district, Sierra de Cacheuta, La Rioja Province, Argentina (type locality). It was named for Oscar Schmieder (1891–1980), German geographer.[3]
References
edit- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ Schmiederite on Webmineral
- ^ a b c Schmiederite on Mindat.org
- ^ a b Handbook of Mineralogy