Xitieshanite
| Xitieshanite | |
|---|---|
| General | |
| Category | Sulfate mineral |
| Formula (repeating unit) | Fe3+(SO4)Cl·6(H2O) |
| IMA symbol | Xit[1] |
| Strunz classification | 7.DC.20 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | P21/a |
| Unit cell | a = 14.1 Å, b = 6.9 Å c = 10.67 Å; β = 111.26°; Z = 4 |
| Identification | |
| Formula mass | 313.47 g/mol |
| Color | Green; yellow green |
| Crystal habit | Acicular |
| Cleavage | Uncertain / indistinct |
| Fracture | Conchoidal to uneven |
| Mohs scale hardness | 2.5 - 3 |
| Luster | Vitreous |
| Streak | Yellow |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 1.99 |
| Optical properties | Biaxial (-) |
| Refractive index | nα = 1.536 nβ = 1.570 nγ = 1.628 |
| Birefringence | 0.092 |
| Pleochroism | Colorless (x) to pale yellow (y) to light greenish yellow (z) |
| 2V angle | Measured: 77° |
| Dispersion | r > v |
| References | [2][3] |
Xitieshanite is a hydrous iron sulfate–chloride mineral with chemical formula: Fe3+(SO4)Cl·6(H2O).
It was discovered in 1983 and named for the discovery location of Xitieshan lead/zinc ore deposit in the Qinghai Province, China. It was approved by the IMA in the year of its discovery.[4] The mineral has also been reported in 2005 from acid mine drainage from a coal mine in Green Valley, Vigo County, Indiana.[5]
Properties
Xitieshanite mainly consists of oxygen (56.14%) and iron (17.82%), but otherwise contains chlorine (11.31%), sulphur (10.23%) and hydrogen (4.50%). This mineral grown in lead-zinc mines, in the oxidation zone of it. Xitieshanite is a pleochroic mineral, which is an optical phenomenon, meaning the mineral appears as if it's changing colors depending on the axis it is being inspected at. On the X axis it appears as it's colorless, while it looks pale yellow if viewed on the Y axis, and light greenish yellow on the Z axis. It doesn't show any radioactive properties whatsoever.[4]
References
- ^ 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.
- ^ Xitieshanite mineral data from Webmineral
- ^ Mindat.org
- ^ a b "Xitieshanite Mineral Data". www.webmineral.com. Retrieved 2022-03-10.
- ^ Melchiorre, Erik, et al., A new occurrence of xitieshanite [Fe3+(SO4)Cl·6H2O] crystals in acid-mine seepways, Green Valley, Vigo County, Indiana, U.S.A., American Mineralogist, v. 90 no. 10 p. 1518-1521, 2005