Chaidamuite
| Chaidamuite | |
|---|---|
| General | |
| Category | Sulfate minerals |
| Chemical formula | ZnFe3+(SO4)2(OH)·4(H2O) |
| Strunz classification | 07.DC.30 |
| Crystal symmetry | Triclinic pedial 1 - pseudomonoclinic |
| Unit cell | a = 7.309(2) Å, b = 7.202(2) Å, c = 9.691(3) Å; α = 89.64(3)°, β = 105.89(1)°, γ = 91.11(1)°; Z = 2 |
| Identification | |
| Color | Brown to yellow-brown |
| Crystal system | Triclinic |
| Cleavage | On {001} and {100}, perfect. |
| Fracture | conchoidal |
| Mohs scale hardness | 2.5–3 |
| Luster | Vitreous |
| Streak | Pale yellow |
| Diaphaneity | Translucent |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.632 nβ = 1.640 nγ = 1.688 |
| Birefringence | δ = 0.056 |
| Pleochroism | Strong: X= pale yellow, colorless; Y= pale yellow; z= Brownish yellow |
| 2V angle | 44° |
| References | [1][2][3][4] |
Chaidamuite is a sulfate mineral that was first found in Xitieshan mine south of Mt. Qilianshan in the Chaidamu basin, Qinghai (Chinghai) Province, China. It is named from locality and is a hydrated sulfate containing a hydroxyl and four dihydrogen monoxide molecules. It a secondary mineral possibly formed due to mining process.
Contents |
[edit] Composition
Chemistry: ZnFe3+(SO4)2(OH)·4H2O
[edit] Structure
The crystal structure has been determined by the Patterson method and Fourier syntheses and refined by the full-matrix least-squares method to an R factor of 0.032, using 2833 independent reflections. In the structure, a zigzag chain consists of [Fe(1)O5(OH)] and [Fe(2)O5(OH)] octahedra sharing the OH corners, and an octahedral-tetrahedral chain running parallel to the b axis consists of the zigzag chain of Fe octahedra and (SO4) tetrahedra sharing four pairs of octahedral corners on either side of the zigzag chains. These chains are cross-linked by the isolated [Zn(1)O2(H2O)4] and [Zn(2)O2(H2O)4] octahedra into corrugated sheets parallel to the (100) plane. Adjacent sheets are hydrogen bonded through water molecules (Li, et al 1990).
[edit] References
- ^ Li, W.M., and Wang, Q.G. (1990) Determination and Refinement of the Crystal Structure of Chaidamuite (Issue 5). Science in China Series B-Chemistry, 33, 623-630
- ^ Mindat.org
- ^ Webmineral data
- ^ Handbook of Mineralogy
[edit] Bibliography
- Clark, A.M. (1993) Hey’s Mineral Index (3rd edition). Alphabetical Index of Mineral Species, Varieties and Synonyms and Chemical Classification. 121 p. Chapman & Hall, New York, NY.
- Jambor, J.L., and Burke, E.A.J. (1990) New Mineral Names. American Mineralogist, 75, 1431-1437.
- Li, W., Chen, G., and Peng, Z. (1986) Chaidamuite. Acta Mineralogica Sinica, 6, 109.
- Li, W.M., and Wang, Q.G. (1990) Determination and Refinement of the Crystal Structure of Chaidamuite (Issue 5). Science in China Series B-Chemistry, 33, 623-630
- Mandarino, J.A., and de Fourestier, J., (2005) Mineral Species First Found in People’s Republic of China. (No. 2). Rocks and Minerals, 80, 114-117.
