May 20 2014
Burpalite was named after its occurrence in the Burpala massif, Russia.
Properties of Burpalite
The following are the key properties of burpalite:
- Cell Data
- Space group: P21/a
- a = 10.1173(8)
- b = 10.4446(6)
- c = 7.2555(3)
- β = 90:039(7)°
- Z = 4
- Crystal Data
- Monoclinic, pseudo-orthorhombic
- Point group: 2/m
- As tablets, elongated along [001] and flattened on {010}, to 5mm
- In fan-shaped aggregates, commonly intimately intergrown with lavenite
- X-ray powder pattern: 2.962 (vs), 1.886 (ms), 1.556 (ms), 1.787 (s), 3.035 (m), 3.306 (m), 1.678 (m)
- Chemical Composition
| Elements |
Content 1 |
| SiO2 |
31.82 |
| ZrO2 |
31.11 |
| CaO |
14.52 |
| Na2O |
13.86 |
| F |
8.1 |
| -O = F2 |
3.41 |
| H2O |
1.23 |
| TiO2 |
1.06 |
| MnO |
0.60 |
| FeO |
0.43 |
| Y2O3 |
0.32 |
| Nb2O5 |
0.22 |
| Total |
99.86 |
- Optical Properties
- Optical class: Biaxial (-)
- Orientation: X = b; Y = c; Z = a
- Dispersion: r < v, weak
- α = 1.627(2); β = 1.634(2); γ = 1.639(2)
- 2V(meas.) = 82.1°
- 2V(calc.) = 80.1°
- Estimated Properties
| Electron density |
Bulk density (electron density) = 3.19 g/cm3
note: Specific gravity of burpalite = 3.32 g/cm3 |
| Photoelectric |
PEBurpalite = 34.00 barns/electron
U=PEBurpalite x ρ electron density = 108.34 barns/cm3 |
| Fermion index |
Fermion index = 0.03
Boson index = 0.97 |
Radioactivity
|
Burpalite is not radioactive
|
How to Identify Burpalite
Burpalite can be identified in the field by its yellowish color. It is sometimes colorless. Its transparent to translucent form has good cleavage. This mineral has a vitreous luster, with white streak.
The density of burpalite is 3.33 g/cm3 with a hardness of 5 to 6 - between apatite and orthoclase.
Global Distribution
Burpalite is distributed mainly in the Burpala massif, about 120km north of Lake Baikal, eastern Siberia, in Russia.
Occurrence of Burpalite and Useful Mineral Association
Burpalite occurs in a fenitized hornfelsic sandstone in the contact zone of an alkalic intrusive.
It is often associated with minerals such as Lavenite, albite, nepheline, aegirine, loparite, alkalic amphibole, biotite, catapleiite, astrophyllite, and fluorite.
References