Jun 13 2014
Bariopyrochlore was named by the IMA committee on pyrochlore nomenclature, based on the major content, barium, in the composition, and its membership of the pyrochlore group.
Properties of Bariopyrochlore
The following are the key properties of bariopyrochlore:
- Cell Data
- Space group: Fd3m
- a = 10.562(6)
- Z = 8
- Crystal Data
- Cubic
- Point group: 4/m 3 2/m
- As crude to anhedral crystals, to 1mm, showing cube and octahedron faces; granular, porous due to alteration or recrystallization
- X-ray powder pattern: 3.044 (100), 6.09 (80), 1.864 (70), 1.590 (70), 1.0164 (60), 3.18 (50), 1.210 (50)
- Chemical Composition
| Elements |
Content 1 |
Content 2 |
| Nb2O3 |
69.06 |
65.60 |
| BaO |
12.88 |
15.31 |
| H2O+ |
4.11 |
8.17 |
| SrO |
6.60 |
trace |
| TiO2 |
3.87 |
4.63 |
| S Ce2O3 |
2.06 |
2.17 |
| CaO |
0.86 |
1.37 |
| ThO2 |
0.62 |
0.92 |
| Ta2O5 |
0.23 |
0.57 |
| MgO |
- |
0.57 |
| FeO |
0.44 |
- |
| Na2O |
0.28 |
0.23 |
| K2O |
0.15 |
0.23 |
| PbO |
- |
0.23 |
| F |
trace |
- |
| Total |
[101.16] |
[100.00] |
- Optical Properties
- Optical class: Isotropic
- n = 2.07–2.11
- Estimated Properties
| Electron density |
Bulk density (electron density) = 3.67 g/cm3
note: Specific gravity of bariopyrochlore = 4.00 g/cm3 |
| Photoelectric |
PEbariopyrochlore = 134.09 barns/electron
U = PEbariopyrochlore x ρ electron density = 491.47 barns/cm3 |
| Fermion index |
Fermion index = 0.02
Boson index = 0.98 |
Radioactivity
|
Bariopyrochlore is not radioactive
|
How to Identify Bariopyrochlore
Bariopyrochlore can be identified in the field by its color variations, such as green-gray, and yellow-gray. Its transparent to translucent form has {111} indistinct, {111} indistinct, {111} indistinct cleavage. This mineral has a resinous luster, with white streak. The fracture on this mineral is brittle-conchoidal.
The density of bariopyrochlore is 4 g/cm3, with a hardness of 4.5 to 5 – approximate to near apatite.
Global Distribution
Bariopyrochlore is distributed in the following places:
- Tanzania - From the Mbeya carbonatite, Panda Hill, near Mbeya
- Congo (Zaire) - From the Bingo deposit, Kivu Province
- Kenya - In the Mrima Hill carbonatite
- Brazil - In a deposit of several hundred million tons at Arax´a, Minas Gerais, and in the Catalao II carbonatite, Goias
- Russia - At an undefined locality in Primorskiy Kray
- USA - From Dehnel’s pit, Stettin, Marathon Co. Wisconsin
Occurrence of Bariopyrochlore and Useful Mineral Association
Bariopyrochlore occurs at the contact zone of a highly weathered, biotite-rich rock, in a roof pendant in a carbonatite, in weathered carbonatite, and in an alkalic aegerine-albite-microcline metasomatite in nepheline syenite.
It is often associated with minerals such as biotite, fluorite, quartz, kaolinized feldspar, zircon, chlorite, plagioclase, apatite, rutile, zircon, hematite, limonite, and aegirine.
References