Meta-Ankoleit
| Meta-Ankoleit | |
|---|---|
 |
|
| General and classification | |
| other names |
IMA 1963-013 |
| chemical formula |
|
|
Mineral class (and possibly department) |
Phosphates, arsenates, vanadates |
|
System no. to Strunz and to Dana |
8.EB.15 ( 8th edition : VII / D.20b) 40.02a.08.01 |
| Crystallographic Data | |
| Crystal system | tetragonal |
| Crystal class ; symbol | 4 / mmm |
| Space group | P 4 / nmm (No. 129) |
| Lattice parameters | a = 6.993 Å ; c = 8.891 Å |
| Formula units | Z = 1 |
| Physical Properties | |
| Mohs hardness | 2 to 2.5 |
| Density (g / cm 3 ) | 3.54 |
| Cleavage | perfectly |
| Break ; Tenacity | uneven |
| colour | yellow |
| Line color | pale yellow |
| transparency | translucent, see-through |
| shine | Glass gloss |
| radioactivity | radioactive |
| Crystal optics | |
| Refractive indices |
n α = 1.580 n γ = 1.560 |
| Birefringence | δ = 0.020 |
| Other properties | |
| Special features | yellow-green fluorescence at 365 nm and 245 nm |
Meta-Ankoleit (also Metaankoleit ) is a very rarely occurring mineral from the mineral class of "phosphates, arsenates and vanadates". It crystallizes in the tetragonal crystal system with the composition K (UO 2 ) (PO 4 ) · 3H 2 O and chemical point of a hydrous potassium - uranyl - phosphate .
Meta-Ankoleit develops only very small, pale yellow crystals and is known from only eight localities so far.
Etymology and history
The mineral was named in 1966 after its type locality, the Ankole pegmatite field in Uganda.
classification
Already in the outdated 8th edition of the mineral classification by Strunz meta Ankoleit belonged to the mineral class of "phosphates, arsenates and vanadates" and then to the department "water containing phosphates, arsenates and vanadates with foreign anions " where he along with abernathyite , meta- autunite , Metabassetit (discredited because identical to Bassetit) Metaheinrichit , Metakahlerit , Metakirchheimerit , Metanatroautunit , Metanatrouranospinit , Metanováčekit , Metatorbernit , Metauramphit (mineral status at the time in question), Metauranocircit , Metauranospinit , Metazeunerit , Sincosit and Trögerit the "meta-Uranit series “With the system no. VII / D.20b .
In the last revised and updated Lapis mineral directory by Stefan Weiß in 2018 , which, out of consideration for private collectors and institutional collections, is still based on this old form of Karl Hugo Strunz's system , the mineral was given the system and mineral number. VII / E.02-140 . In the "Lapis system" this corresponds to the section "Uranyl phosphates / arsenates and uranyl vanadates with [UO 2 ] 2+ - [PO 4 ] / [AsO 4 ] 3- and [UO 2 ] 2+ - [V 2 O 8 ] 6- , with isotypic vanadates (sincosit-R.) ", Where meta-ankolite together with abernathyite, bassetite , chernikovite , lehnerite , meta-autunite, metaheinrichite, metakahlerite, metakirchheimerite , metalodèvite , metanatroautuchunite , metanovarauchunite , Metasaleeit , Metatorbernit, Metauranocircit , Metauranospinit , Metazeunerit, Natrouranospinit , Pseudo-Autunit , Ulrichit , Uramarsit and Uramphit form the "Meta-Autunit-Gruppe".
The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and was updated by the International Mineralogical Association (IMA) until 2009, also classifies the Meta-Ankoleit in the "Uranylphosphate and Arsenate" department. However, this is further subdivided according to the ratio of uranium oxide complex (UO 2 ) to phosphate, arsenate or vanadate complex (RO 4 ), so that the mineral according to its composition in the subdivision "UO 2 : RO 4 = 1: 1" can be found where it forms the unnamed group 8.EB.15 together with abernathyite, chernikovite, natrouranospinite, trögerite , uramarsite and uramphite .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Meta-Ankoleit to the class of "phosphates, arsenates and vanadates" and there in the department of "water-containing phosphates etc.". Here he is the only member of the unnamed group 40.02a.08 within the subdivision " Water-containing phosphates etc., with A 2+ (B 2+ ) 2 (XO 4 ) × x (H 2 O), with (UO 2 ) 2+ ”can be found.
Crystal structure
Meta-Ankoleit crystallizes tetragonally in the space group P 4 / nmm (space group no. 129) with the lattice parameters a = 6.993 (10) Å ; and c = 8.891 (5) Å and one formula unit per unit cell .
properties
The mineral is very radioactive due to its uranium content of up to 52.0 % by weight . Taking into account the natural decay chains is a meta tag Ankoleit specific activity of about 93.0 k Bq stated / g (compared to natural potassium 0.0312 kBq / g).
Education and Locations
Meta-Ankoleit is only known from eight sites: from the San Miguel Prospection in Chile, from Saint-Yrieix-la-Perche in France, from Tirpersdorf in Saxony, from Arcu su Linnarbu in Sardinia, from four deposits in the USA (Virgin Valley , Nevada; Stirling Mine, New Jersey; Pueblo Mining District, Oregon; Blue Lizard Mine, Utah), from Zimbabwe and from the type locality, the Ankole pegmatite field in Uganda.
Meta-Ankoleit is a rare secondary uranium mineral from the weathering zone of complex granite pegmatites such as in the Mungenyi pegmatite in Uganda and sericite matrix of quartz and sandstone (Sebungwe district, Zimbabwe).
See also
Web links
- Mineral Atlas: Meta-Ankoleit (Wiki)
Individual evidence
- ↑ a b c Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: January 2020. (PDF 1729 kB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, January 2020, accessed February 19, 2020 .
- ^ 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 (English).
- ^ A b c David Barthelmy: Meta-ankoleite Mineral Data. In: webmineral.com. Retrieved February 19, 2020 .
- ↑ a b c d meta-ankoleite. In: mindat.org. Hudson Institute of Mineralogy, accessed February 19, 2020 .
- ↑ a b MJ Gallagher, D. Atkin: Meta-ankoleïte, hydrated potassium uranyl phosphate . In: Bulletin of the Geological Survey of Great Britain . tape 25 , 1966, pp. 49–54 (English, rruff.info [PDF; 455 kB ; accessed on February 19, 2020]).
- ↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
- ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1816 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed February 19, 2020 .
- ↑ meta ankoleite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 (English, handbookofmineralogy.org [PDF; 66 kB ; accessed on February 19, 2020]).