Chernikovite
| Chernikovite | |
|---|---|
 |
|
| General and classification | |
| chemical formula | (H 3 O) 2 [UO 2 | PO 4 ] 2 · 6 (H 2 O) |
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.EB.15 ( 8th edition : VII / E.02) 40.02a.19.01 |
| Crystallographic Data | |
| Crystal system | tetragonal |
| Crystal class ; symbol | 4 / mmm |
| Space group | P 4 / nmm (No. 129) |
| Lattice parameters | a = 7.02 Å ; c = 9.05 Å |
| Formula units | Z = 1 |
| Physical Properties | |
| Mohs hardness | 2 to 2.5 |
| Density (g / cm 3 ) | 3.259 |
| Cleavage | perfect after {001}, good after {100} |
| Break ; Tenacity | micaceous |
| colour | light yellow |
| Line color | yellowish white |
| transparency | transparent to translucent |
| shine | Please complete |
| radioactivity | very strong |
| Crystal optics | |
| Refractive indices |
n α = 1.580-1.583 n γ = 1.569-1.570 |
| Optical character | uniaxial negative |
| Axis angle | 2V = 5 to 10 ° |
| Other properties | |
| Special features | radioactive |
Chernikovite is a very rare mineral from the mineral class of phosphates , arsenates and vanadates . It crystallizes in the tetragonal crystal system with the chemical composition (H 3 O) 2 [UO 2 | PO 4 ] 2 · 6 (H 2 O) and forms light yellow, thin, tabular crystals . It is often found in paragenesis with autunit and meta-autunit.
Etymology and history
There is evidence that Chernikovit was found around 1910 by the mountain director Ernst Julius Fröbe (1851–1921) in the Rockelmann quarry near Schwarzenberg . The mineral was discovered in 1988 on the proposal of J. Atencio in honor of Dr. Andrei Andreevich Chernikovs (1927-2013) named. Chernikov first described naturally occurring samples as a hydrogen autunit in 1958. The type mineral is located at the Russian Academy of Sciences in the Mineralogical Museum " Alexander Fersman " in Moscow , Russia . under catalog number 88655. Naturally occurring samples have not yet been thoroughly investigated, all data are based on investigations of synthetic material.
classification
In the Strunz system , Chernikovite is counted among the uranyl phosphates and arsenates. After the 8th edition , it forms together with abernathyite , Bassetit , Lehnerit , Metaankoleit , Metaautunit , Metaheinrichit , Metakahlerit , Metakirchheimerit , Metalodèvit , Metanatroautunit ( meta-sodium Autunit ) Metanováčekit , Metatorbernit , Metauranocircit , Metauranospinit , Metazeunerit , Natrouranospinit , Pseudoautunit , Ulrichit , Uramarsit and Uramphit the Metautunit group. In the 9th edition , the uranyl phosphates and arsenates are divided according to the ratio of uranyl to phosphate / arsenate ions, here it forms with Abernathyit, Meta-Ankoleit, Natrouranospinit (Rn), Trögerite, Uramarsit ( IMA 2005-043 ) and Uramphite a subgroup of uranyl phosphates with a ratio of UO 2 to P / AsO 4 of 1: 1.
In the Dana system , it forms its own subgroup 40.02a.19 of the water-containing phosphates etc. with the general structure A 2+ (B 2+ ) 2 (XO 4 ) x (H 2 O), the (UO 2 ) 2 + .
Crystal structure
Chernikovit crystallizes tetragonally in the space group P 4 / nmm (space group no. 129) with the lattice parameters a = 7.02 Å and c = 9.05 Å and with one formula unit per unit cell.
properties
Due to its uranium content of up to 54.34%, the mineral is very radioactive . Taking into account the natural series of decay or any decay products present, the specific activity is given as 97.26 k Bq / g (for comparison: natural potassium 31.2 Bq / g). It fluoresces intensely yellow-green under UV light.
Education and Locations
Chernikovite forms on quartz in syenite fissures, on petrified wood (Karakat, Tajikistan) and in tourmaline-containing granites and granitic pegmatites (Brazil). Depending on where it was found, it is associated with autunite, metaautunite, uranophane , phosphuranylite , torbernite or meta-torbernite, Haiweeit and "Uranopal".
Only a small number of places where the Chernikovit was found is known. In addition to the type locality, the Karakat uranium deposit 50 km northeast of the city of Khujand in the Karamazar Mountains in Tajikistan , it was found in the sub-prefecture of Peru, 25 km north of São Paulo , Brazil , near San Giacomo Vercellese in Piedmont in Italy , near Chãs de Tavares , Mangualde County in Portugal , the Khiagda uranium deposit in Eastern Siberia, Russia , the Laguna District ( New Mexico ) and Mayfield , Fulton County (New York) in the USA . In Germany it was found in Saxony in the Rockelmann quarry near Schwarzenberg, in Thuringia near Ronneburg and in Bavaria near Mähringen and Hagendorf .
Precautions
Due to the high level of radioactivity and toxicity , mineral samples from Chernikovit should only be kept in dust- 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
literature
Chernikovite in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( pdf ).
Web links
Individual evidence
- ↑ a b c d e 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. 526 .
- ↑ a b c Mindat - Chernikovite
- ↑ a b Webmineral - Chernikovite
- ↑ a b Fosfatos e silicatos secundarios de uranio de Perus, Sao Paulo , In: Daniel Atencio & Raphael Hypolito (eds.): Revista Brasileira de Geociências , 1994 ( Link )
- ↑ a b Webmineral.ru - Chernikovite
- ↑ a b Chernikovite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 68 kB )