| Langite | |
|---|---|
 Langite from Podlipa and Reinera Mines, Slovakia | |
| General | |
| Category | Copper minerals |
| Formula (repeating unit) | Cu4(SO4)(OH)6·2H2O |
| IMA symbol | Lgt[1] |
| Strunz classification | 7.DD.10 |
| Dana classification | 31.4.3.1 |
| Crystal system | Monoclinic |
| Crystal class | Domatic (m) (same H-M symbol) |
| Space group | Pc |
| Unit cell | a = 7.118, b = 6.031 c = 11.209 [Å] β = 90.00–90.02°; Z = 2 |
| Identification | |
| Formula mass | 488.32 g/mol |
| Color | Greenish blue, sky-blue to bluish green |
| Crystal habit | Crystals scaly, or as crusts; earthy |
| Twinning | Common on {110}, typically repeated |
| Cleavage | {001} perfect, {010} distinct |
| Fracture | Uneven |
| Mohs scale hardness | 2.5 to 3 |
| Luster | Vitreous, crusts silky |
| Streak | Blue green |
| Diaphaneity | Translucent |
| Specific gravity | 3.28[3] 3.48 to 3.5[2] 3.5[4] 2.28 to 3.34[5] |
| Optical properties | Biaxial (−) r>v weak |
| Refractive index | nα = 1.708 nβ = 1.760 nγ = 1.798 [2] |
| Birefringence | δ = 0.090 |
| Pleochroism | X = c = light yellowish green Y = b = blue-green Z = a = sky blue |
| Solubility | Insoluble in water, easily soluble in dilute acids or NH4OH |
| Other characteristics | May be altered to brochantite. Not radioactive |
| References | [2][3][4][5] |
Langite is a rare hydrated copper sulfate mineral, with hydroxyl, found almost exclusively in druses of small crystals. It is formed from the oxidation of copper sulfides, and was first described in specimens from Cornwall, United Kingdom. It is dimorphous with wroewolfeite. Langite was discovered in 1864 and named after the physicist and crystallographer Viktor von Lang (1838–1921), who was Professor of Physics at the University of Vienna, Austria.[2]
- ^ 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.
- ^ a b c d Mindat.org
- ^ a b Gaines et al (1997) Dana’s New Mineralogy Eighth Edition, Wiley
- ^ a b Webmineral data
- ^ a b Handbook of Mineralogy