Chaidamuite

Chaidamuite
General
Category Sulfate minerals
Formula
(repeating unit)
ZnFe3+(SO4)2(OH)·4(H2O)
Strunz classification 07.DC.30
Crystal symmetry Triclinic pedial
H-M symbol: (1) Space group: P1
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 habit Tabular pseudocubic crystals and granular masses
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 rare zinc – iron sulfate mineral with chemical formula: ZnFe3+(SO4)2(OH)·4H2O.

It was first described for an occurrence in the Xitieshan mine south of Mt. Qilianshan in the Chaidamu basin, Qinghai Province, China and was named for the locality. It occurs as an oxidation phase in a lead zinc deposit. In the type locality it is associated with the rare minerals: coquimbite, copiapite, butlerite and zincobotryogen.[4] In addition to the Chinese occurrence it has been reported from the Getchell Mine in the Potosi District in Humboldt County, Nevada.[2]

References

  1. 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
  2. 2.0 2.1 Mindat.org
  3. Webmineral data
  4. 4.0 4.1 Handbook of Mineralogy

Bibliography