Biehlite– Occurrence, Properties, and Distribution

Biehlite was named after Dr. Friedrich Karl Biehl (1887–), a mineralogist, associated with the Westfalische-Wilhelms University in Munster, Germany, who worked on an early dissertation on the Tsumeb species.

Properties of Biehlite

The following are the key properties of biehlite:

  • Cell Data
    • Space group: C2/c
    • a = 18.076(5)
    • b = 5.920(5)
    • c = 5.083(5)
    • β = 96.97(1)°
    • Z = 4

  • Crystal Data
    • Monoclinic
    • Point group: 2/m
    • Crystals are fibrous, to 1cm, elongated along [001], in felted masses and irregular aggregates
    • X-ray powder pattern: 2.990 (100), 2.960 (100), 5.622 (65), 3.104 (61), 2.104 (42), 3.376 (39), 1.962 (32)

  • Chemical Composition
Elements Content 1
Sb2O3 60.99
MoO3 33.76
As2O3 4.95
Total 99.70

  • Optical Properties
    • Optical class: [Biaxial]
    • n = [2.13] (by the rule of Gladstone and Dale)
    • α = n.d.; β = n.d.; γ = n.d.
    • 2V(meas.) = n.d

  • Estimated Properties
Electron density Bulk density (electron density) = 4.63 g/cm3
note: Specific gravity of biehlite = 5.24 g/cm3
Photoelectric PE Biehlite = 212.55 barns/electron
U = PE Biehlite x ρ electron density = 984.96 barns/cm3
Fermion index Fermion index = 0.05
Boson index = 0.95
Radioactivity Biehlite is not radioactive

How to Identify Biehlite

Biehlite can be identified in the field by its white color. Its translucent form has a vitreous-silky luster, with white streak. The fracture on this mineral is flexible.

The hardness of biehlite is 1 to 1.5 – approximate to talc, or a little harder.

Global Distribution

Biehlite is distributed mainly in Tsumeb, Namibia.

Occurrence of Biehlite and Useful Mineral Association

Biehlite occurs in a rare secondary mineral from an oxidized zone in a dolostone-hosted hydrothermal polymetallic ore deposit.

It is often associated with minerals such as anglesite and wulfenite.

References

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