Bauranoite
| Bauranoite | |
|---|---|
 |
|
| General and classification | |
| other names |
IMA 1971-052 |
| chemical formula | Ba [(UO 2 ) 2 | O 3 ] • 4-5H 2 O |
|
Mineral class (and possibly department) |
Oxides and hydroxides |
|
System no. to Strunz and to Dana |
4.GB.20 ( 8th edition : IV / H.06) 04/05/02/02 |
| Similar minerals | Calciouranoite , metacalciouranoite , wölsendorfite |
| Crystallographic Data | |
| Crystal system | triclinic |
| Crystal class ; symbol | not defined |
| Physical Properties | |
| Mohs hardness | 5 |
| Density (g / cm 3 ) | measured: 5.283 to 5.420 |
| Cleavage | Please complete |
| colour | reddish brown |
| Line color | Please complete |
| transparency | translucent |
| shine | Please complete |
| radioactivity | very radioactive |
| Crystal optics | |
| Refractive indices |
n α = 1.911 to 1.916 n γ = 1.920 to 1.932 |
| Birefringence | δ = 0.009 to 0.016 |
| Optical character | biaxial negative |
| Axis angle | 2V = measured: 81 ° |
| Other properties | |
| Special features | toxic |
Bauranoite is a very rarely occurring mineral from the mineral class of " oxides and hydroxides ". It crystallizes in the triclinic crystal system with the chemical composition Ba [(UO 2 ) 2 | O 3 ] • 4-5H 2 O and develops mainly massive, fine-grained aggregates of reddish-brown color.
Etymology and history
Was first discovered Bauranoit with Metacalciouranoit 1971 in molybdenum - uranium - deposit Strelzowskoje in Krasnokamensk in the Russian region of Trans-Baikal and described by VP Rogova, LN Belova, GN Kiziyarov and NN Koznetsova that the mineral in most of its components barium (Ba) and named uranium. After the mineral and its name were recognized by the International Mineralogical Association (register no. IMA 1971-052 ), the test results and the recognized name were published in 1973 in the scientific magazine "American Mineralogist" (58, 1111).
classification
In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the bauranoite belonged to the mineral class of "oxides and hydroxides" and there to the department of "uranyl hydroxides and hydrates", where together with calciouranoite , metacalciouranoite and wölsendorfite it was one formed an independent group.
The 9th edition of Strunz's mineral systematics, which has been valid since 2001 and is used by the IMA, assigns the bauranoite to the class of "oxides and hydroxides" and there in the department of "uranyl hydroxides". However, this section is further subdivided according to the possible presence of additional cations and the crystal structure, so that the mineral is classified in the sub-section “With additional cations (K, Ca, Ba, Pb etc.); with predominantly UO 2 (O, OH) 5 pentagonal polyhedra "is to be found, where together with calciouranoite and metacalciouranoite the" calciouranoite-bauranoite group "with the system no. 4.GB.20 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the bauranoite to the class of "oxides and hydroxides" and there in the department of "uranium and thorium-containing oxides". Here it can be found together with calciouranoite in the unnamed group 04/05/02 within the sub-section “ Oxides containing uranium and thorium containing alkaline earth metal elements (containing water) ”.
Crystal structure
Bauranoite crystallizes in the triclinic crystal system, but no data on the space group or the lattice parameters are available yet.
properties
The mineral is toxic due to its barium content of around 17% and classified as very radioactive due to its uranium content of up to 59% and has a specific activity of around 105.67 k Bq / g (for comparison: natural potassium 31.2 Bq /G).
Education and Locations
Bauranoit forms metamorph in the oxidation zone of uranium - molybdenum - deposits , where the one hand, uraninite ( pitchblende replaced) and on the other hand by Uranophan is replaced. Accompanying minerals are accordingly uraninite and uranophane, but also calciouranoite , metacalciouranoite and protasite .
So far (status: 2011) Bauranoite could only be detected at its type locality Strelzowskoje near Krasnokamensk in Russia.
Precautions
Due to the toxicity and the high level of radioactivity of the mineral, samples should only be stored in dust- and radiation-tight containers, but especially never in living rooms, bedrooms or workrooms. Absorption into the body (orally) should also be prevented in any case and, for safety, direct body contact should be avoided and a respirator and gloves should be worn when handling the mineral .
See also
Individual evidence
- ^ A b Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 251 .
- ↑ a b Webmineral - Bauranoite (English)
- ↑ a b Handbook of Mineralogy - Bauranoite (English, PDF 63.1 kB).
- ↑ a b c d Bauranoite at mindat.org (English) .
literature
- VP Rogova, LN Belova, GN Kiziyarov, NN Kuznetsova (1973): Bauranoite and metacaltsuranoite [metacalciouranoite] - new minerals of the group of hydrous uranium oxides . Zap. Vses. Mineral. Obshch., 102, 75-81 (russian) and American Mineralogist, 58, 1111 ( PDF (English), 558 kB ).
Web links
- Mineral Atlas: Bauranoite (Wiki)