Strelkinite
| Strelkinite | |
|---|---|
 |
|
| General and classification | |
| other names |
IMA 1973-063 |
| chemical formula | Na 2 (UO 2 ) 2 V 2 O 8 · 6H 2 O |
|
Mineral class (and possibly department) |
Oxides and hydroxides |
|
System no. to Strunz and to Dana |
4.HB.30 ( 8th edition : VII / E.11) 40.02a.29.01 |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | orthorhombic-dipyramidal; 2 m 2 m 2 m |
| Room group (no.) | Pnmm (No. 59) |
| Lattice parameters | a = 10.64 Å ; b = 8.36 Å; c = 32.72 Å |
| Formula units | Z = 8 |
| Physical Properties | |
| Mohs hardness | 2 to 2.5 |
| Density (g / cm 3 ) | 4 to 4.2 |
| Cleavage | completely after {001} |
| colour | greenish yellow, golden yellow |
| Line color | light yellow |
| transparency | translucent |
| shine | Silky gloss, mother-of-pearl, |
| radioactivity | radioactive |
| Crystal optics | |
| Refractive indices |
n α = 1.674 to 1.770 n β = 1.855 to 1.907 n γ = 1.880 to 1.915 |
| Birefringence | δ = 0.143 |
| Optical character | biaxial negative |
| Pleochroism | weak: X = colorless, Y = yellow, Z = light yellow |
| Other properties | |
| Chemical behavior | soluble in acids |
| Special features | weak green fluorescence under short-wave UV light |
Strelkinite is a rarely occurring uranium - vanadium mineral from the mineral class of " oxides and hydroxides ". It crystallizes in the orthorhombic crystal system with the chemical composition Na 2 (UO 2 ) 2 V 2 O 8 · 6H 2 O and thus represents the sodium analogue of the mineral carnotite . It usually develops golden-yellow to green-yellow, fan-shaped mineral aggregates that become crusty Coatings can be connected, but rarely also tabular crystals up to 1.5 mm in size.
Etymology and history
Strelkinite bears the name of the Russian mineralogist Prof. Mikhail Fedorovich Strelkin (1905–1965), who examined uranium minerals in particular. It was found for the first time in 1965 in SiO 2 -rich sediments of the Paleozoic and later also in Devonian silica schist on the territory of the former USSR . Further investigations were carried out in 1974 by MA Alekseeva et al. instead of. The type mineral is located at the Russian Academy of Sciences in the Mineralogical Museum " Alexander Fersman " in Moscow , Russia (catalog numbers 74783 and 74784).
classification
In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the Strelkinite belonged to the mineral class of " phosphates , arsenates and vanadates " and there to the department of "uranyl phosphates / arsenates and uranyl vanadates ", where it belongs together with carnotite , curienite , Francevillit , Margaritasit , Metatyuyamunit , Metavanuralit , Sengierit , Tyuyamunit and Vanuralit the group of "Uranyl-Gruppevanadate mit [UO 2 ] 2+ - [V 2 O 8 ] 6− " with the system no. VII / E.11 formed.
The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), assigns Strelkinite to the class of "oxides and hydroxides" and there in the division of "V [5,6] vanadates" . This is further subdivided according to the crystal structure, so that the mineral can be found in the sub-section “Uranyl group vanadates (Sorovanadate)”, where it is in the unnamed group 4.HB.30 .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Strelkinite to the class of "phosphates, arsenates and vanadates" like the outdated Strunz'sche systematics, but there in the category of "water-containing phosphates etc.". Here it is in the unnamed group 40.02a.29 within the subdivision of “Water-containing phosphates etc., with A 2+ (B 2+ ) 2 (XO 4 ) × x (H 2 O), with (UO 2 ) 2+ " to find.
Crystal structure
Strelkinite crystallizes orthorhombically in the space group Pnmm with the lattice parameters a = 10.64 Å ; b = 8.36 Å and c = 32.72 Å as well as 8 formula units per unit cell .
properties
The mineral is highly radioactive due to its uranium content of up to 51.52% . Taking into account the proportions of the radioactive elements in the idealized empirical formula and the Folgezerfälle of the natural decay chains a specific activity of approximately 92.22 k for the mineral Bq stated / g (compared to natural potassium 0.0312 kBq / g). The quoted value can vary significantly depending on the mineral content and the composition of the levels; selective enrichment or depletion of the radioactive decay products is also possible and changes the activity. It shows a weak green fluorescence under short-wave UV light.
Education and Locations
Strelkinite forms in sediments containing silica and carbonate. There it occurs mainly in paragenesis with calcite , quartz , iron hydroxides and clay minerals . Well-known sites include Basaral - 10 km north of the Bota-Burum uranium deposit ( type locality ) - and the Kendyktas Mountains (co-type locality), Schu-Ili Mountains , Almaty Oblast in Kazakhstan and Uzbekistan , the Lisdan-Siwaga fault , Hashem Region in Jordan , as well as the "Fairview Quarry" near Robertstown ( South Australia ) and Pick's Delta Mine, Utah , USA .
Precautions
Due to the toxicity and the strong radioactivity of the mineral, mineral samples from Strelkinit should only be kept in dust- and radiation-proof 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
- Mineral Atlas: Strelkinite (Wiki)
Individual evidence
- ↑ a b c Mindat - Strelkinite (English)
- ↑ a b Webmineral - Strelkinite (English)
- ↑ a b c d Strelkinite in: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 66.5 kB )
- ↑ a b c Strelkinit in: MA Alekseeva et al .: Strelkinit- Ein neue Uranylvanadat (1974) ( PDF 248.5 kB )