Chaidamuite – Occurrence, Properties, and Distribution

Chaidamuite was named after the place of its occurrence, near Chaidamu in China.

Properties of Chaidamuite

The following are the key properties of chaidamuite:

  • Cell Data
    • Space group: P1
    • a = 7.309(2)
    • b = 7.202(2)
    • c = 9.691(3)
    • α = 89.64(3)°
    • β = 105.89(3)°
    • γ = 91.11(2)°
    • Z = 2

  • Crystal Data
    • Triclinic, pseudomonoclinic
    • Point group: 1
    • As thick tabular to pseudocubic crystals, with {001}, {010}, {011}, and {101}
    • As grains or granular aggregates, to < 1mm
    • X-ray powder pattern: 3.118 (100), 3.090 (95), 9.40 (80), 5.00 (80), 3.64 (70), 5.03 (65), 2.048 (40)

  • Chemical Composition
    Elements Content 1 Content 2
    SO3 40.63 39.79
    Fe2O3 20.00 19.84
    H2O 19.21 20.15
    ZnO 17.00 20.22
    FeO 2.09 -
    SiO2 0.15 -
    Al2O3 0.12 -
    MnO 0.06 -
    Na2O 0.02 -
    K2O 0.01 -
    Total 99.29 100.00

  • Optical Properties
    • Optical class: Biaxial (+)
    • Pleochroism: Strong; X = pale yellow to colorless; Y = pale yellow; Z = brownish-yellow
    • Orientation: X = b; Y ^ a = 12°; Z ^ c = 28°
    • Dispersion: r < v, strong
    • α = 1.632(1); β = 1.640(1); γ = 1.688(1)
    • 2V(meas.) = 44(2)°

  • Estimated Properties
    Electron density Bulk density (electron density) = 2.72 g/cm3
    note: Specific gravity of chaidamuite = 2.72 g/cm3
    Photoelectric PE chaidamuite = 12.86 barns/electron
    U=PE chaidamuite x ρ electron density = 34.96 barns/cm3
    Fermion index Fermion index = 0.01
    Boson index = 0.99
    Radioactivity
    Chaidamuite is not radioactive

How to Identify Chaidamuite

Chaidamuite can be identified in the field by its color variations, such as brown and yellowish-brown. Its translucentform has {001} perfect and {100} perfect cleavage. This mineral has a vitreous luster, with light yellow streak.

The density of chaidamuite is 2.722 g/cm3 with a hardness of 2.5 to 3 - between finger nail and calcite. It is non-fluorescent.

Global Distribution

Chaidamuite is distributed mainly in the Xitieshan Pb–Zn mine, south of Mt. Qilianshan, Chaidamu, Qinghai Province, China.

Occurrence of Chaidamuite and Useful Mineral Association

Chaidamuite occurs in a secondary mineral in the oxidized portions of a Pb–Zn–Fe sulfide deposit.

It is often associated with minerals such as coquimbite, copiapite, butlerite, and zincobotryogen.

References

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