Jun 11 2014
Billietite was named after Valere Louis Billiet (1903–1945), a Belgian crystallographer associated with the University of Ghent in Ghent, Belgium.
It is an uncommon mineral of Uranium that contains Barium.
Properties of Billietite
The following are the key properties of billietite:
- Cell Data
- Space group: Pbn21
- a = 12.0720(22)
- b = 30.167(4)
- c = 7.1455(5)
- Z = 4
- Crystal Data
- Orthorhombic
- Point group: mm2
- Crystals: pseudohexagonal, tabular on {001}, may be elongated along [110], to 5mm
- Twinning: Very common, on {110} and {111}, the latter producing sector-twinned aragonite-like groups
- X-ray powder pattern: 7.53 (10), 3.77 (9), 3.17 (8), 2.03 (6), 3.54 (5), 2.49 (4), 2.56 (3)
| Elements |
Content 1 |
Content 2 |
Content 3 |
| UO3 |
82.76 |
84.39 |
86.00 |
| H2O |
8.97 |
8.68 |
6.32 |
| BaO |
6.88 |
7.41 |
7.68 |
| SiO2 |
0.76 |
- |
- |
| CaO |
0.30 |
- |
- |
| Total |
- |
- |
- |
- Optical Properties
- Optical class: Biaxial (-)
- Pleochroism: Distinct; X = colorless to pale yellow; Y = Z = greenish-yellow to deep golden-yellow, amber-brown
- Orientation: X = c; Y = a; Z = b
- Dispersion: r > v, very strong
- α = 1.725–1.730; β = 1.780–1.822; γ = 1.790–1.829
- 2V(meas.) = ∼36°
| Electron density |
Bulk density (electron density) = 4.44 g/cm3
note: Specific gravity of billietite = 5.28 g/cm3 |
| Photoelectric |
PE Billietite = 1,893.82 barns/electron
U = PE Billietite x ρ electron density = 8,414.80 barns/cm3 |
| Fermion index |
Fermion index = 0.01
Boson index = 0.99 |
| Radioactivity |
Billietite is radioactive |
How to Identify Billietite
Billietite can be identified in the field by its color variations, such as yellow-brown and golden-yellow. Its transparent to translucent form has {001} perfect cleavage. This mineral has an adamantine luster, with yellow streak.
The density of billietite is 5.27 to 5.29 g/cm3.
Global Distribution
Billietite is distributed in the following places:
- Congo - From Shinkolobwe and in the Musonoi mine, near Kolwezi, Katanga Province
- France - From the La Crouzille mine, and the Margnac mine, Compreignac, Haute-Vienne, and in the Rabejac uranium deposit, 7km south-south-east of Lodeve, Herault
- Germany - At Wolsendorf, Bavaria; from Menzenschwand
- Wittichen, Black Forest; and at Bergen, Vogtland, Saxony
- USA - On Mauch Chunk Ridge, Jim Thorpe, Carbon Co. Pennsylvania, and in the Delta mine, Emery Co. Utah
Occurrence of Billietite and Useful Mineral Association
Billietite occurs in an uncommon alteration product of uraninite.
It is often associated with minerals such as uranophane, metatorbernite, rutherfordine, fourmarierite, becquerelite, soddyite, and studtite.
References