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
- Point group: 2/m
- Crystals are fibrous, to 1cm, elongated along , 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)
- 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
||Bulk density (electron density) = 4.63 g/cm3
note: Specific gravity of biehlite = 5.24 g/cm3
||PE Biehlite = 212.55 barns/electron
U = PE Biehlite x ρ electron density = 984.96 barns/cm3
||Fermion index = 0.05
Boson index = 0.95
||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.
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.