Chemistry:Melanterite
From HandWiki
Short description: Heptahydrated iron(II) sulfate
| Melanterite | |
|---|---|
 Melanterite as found in nature | |
| General | |
| Category | Sulfate mineral |
| Formula (repeating unit) | FeSO4·7H2O |
| Strunz classification | 7.CB.35 |
| Dana classification | 29.06.10.01 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | P21/c |
| Unit cell | a = 14.077 Å, b = 6.509 Å, c = 11.054 Å; β = 105.6°; Z = 4 |
| Identification | |
| Color | Green, pale green, greenish blue, bluish green, colorless |
| Crystal habit | Encrustations and capillary efflorescences; rarely as equant pseudo-octahedral, prismatic or tabular crystals |
| Cleavage | {001} Perfect, {110} Distinct |
| Fracture | Conchoidal |
| Mohs scale hardness | 2 |
| |re|er}} | Vitreous |
| Streak | White |
| Diaphaneity | Subtransparent to translucent |
| Specific gravity | 1.89 – 1.9 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.470 – 1.471 nβ = 1.477 – 1.480 nγ = 1.486 |
| References | [1][2][3][4] |
Melanterite is a mineral form of hydrous iron(II) sulfate: FeSO4·7H2O. It is the iron analogue of the copper sulfate chalcanthite. It alters to siderotil by loss of water. It is a secondary sulfate mineral which forms from the oxidation of primary sulfide minerals such as pyrite and marcasite in the near-surface environment. It often occurs as a post mine encrustation on old underground mine surfaces. It also occurs in coal and lignite seams exposed to humid air[2] and as a rare sublimate phase around volcanic fumaroles.[4] Associated minerals include pisanite, chalcanthite, epsomite, pickeringite, halotrichite and other sulfate minerals.[4]
It was first described in 1850.[4]
Gallery
Crystal structure of melanterite
Cuprian melanterite
References
- ↑ Mineralienatlas
- ↑ 2.0 2.1 Mindat
- ↑ Webmineral data
- ↑ 4.0 4.1 4.2 4.3 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. https://www.cambridge.org/core/journals/mineralogical-magazine/article/imacnmnc-approved-mineral-symbols/62311F45ED37831D78603C6E6B25EE0A.
 |  |
