Metacalciouranoite
| Metacalciouranoite | |
|---|---|
| General and classification | |
| other names |
|
| chemical formula | (Ca, Na, Ba) [(UO 2 ) 2 | O 3 ] • 2H 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) 04/05/03/01 |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | Please complete |
| Physical Properties | |
| Mohs hardness | Please complete |
| Density (g / cm 3 ) | calculated: 4.90 |
| Cleavage | Please complete |
| colour | orange |
| Line color | Please complete |
| transparency | translucent |
| shine | Please complete |
| radioactivity | very radioactive |
| Crystal optics | |
| Refractive indices |
n α = 1.897 n β = 1.911 n γ = 1.932 |
| Birefringence | δ = 0.035 |
| Optical character | biaxial negative |
| Axis angle | 2V = measured: 81 °; calculated: 80 ° |
Metacalciouranoite is a very rarely occurring mineral from the mineral class of " oxides and hydroxides ". It crystallizes in the orthorhombic crystal system with the chemical composition (Ca, Na, Ba) [(UO 2 ) 2 | O 3 ] · 2H 2 O and has so far only been found in the form of massive to fine-grain mineral aggregates of orange color.
Etymology and history
Was first discovered Metacalciouranoit in the molybdenum - uranium - deposit Strelzowskoje near Krasnokamensk (Eastern Siberia) in Russia and described in 1973 by VP Rogova, LN Belova, GN Kiziyarov and NN Koznetsova that the mineral because of its close relationship to Calciouranoit with less crystal water content named.
classification
In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the metacalciouranoite belonged to the mineral class of "oxides and hydroxides" and there to the department of "uranyl hydroxides and hydrates", where together with bauranoite , calciouranoite and wölsendorfite the unnamed group IV / H.06 formed.
The 9th edition of Strunz's mineral systematics, valid since 2001 and used by the IMA, also assigns metacalciouranoite to the class of "oxides and hydroxides" and the department of "uranyl hydroxides". However, this section is further subdivided according to the presence and type of additional cations as well as the crystal structure, so that the mineral is classified according to its composition in the sub-section “With additional cations (K, Ca, Ba, Pb etc.); with predominantly UO 2 (O, OH) 5 pentagonal polyhedra “, where it forms the unnamed group 4.GB.20 together with bauranoite and calciouranoite .
The systematics of minerals according to Dana also assigns the metacalciouranoite to the class of "oxides and hydroxides" and there in the department of "uranium and thorium-containing oxides". There it is together with wölsendorfite in the unnamed group 04/05/03 within the subdivision “ Oxides containing uranium and thorium containing alkaline earth metal elements (hydrated) ”.
properties
The mineral is classified as very radioactive due to its uranium content of up to 69.58% and has a specific activity of around 124.5 k Bq / g (for comparison: natural potassium 31.2 Bq / g).
Education and Locations
So far, metacalciouranoite could only be detected at its type locality Strelzowskoje near Krasnokamensk in Russia, where it was formed in the oxidation zone of the molybdenum-uranium deposit there. There it occurs in paragenesis with bauranoite , calciouranoite , protasite , uraninite and uranophane .
Precautions
Due to the toxicity and the strong radioactivity of the mineral, mineral samples of metacalciouranoite should only be kept in dust-tight and radiation-tight containers, but especially never in living rooms, bedrooms or work rooms. Absorption into the body (incorporation, ingestion ) should also be prevented in any case and, for safety, direct body contact should be avoided and respiratory protection mask and gloves should be worn when handling the mineral .
See also
Web links
Individual evidence
- ↑ a b Webmineral - Metacalciouranoite (English)
- ↑ a b c d Metacalciouranoite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 59.8 kB )
- ↑ a b c d e f Mindat - Metacalciouranoite
- ^ Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 251 .