Bazirit
| Bazirit | |
|---|---|
 |
|
| General and classification | |
| other names |
IMA 1976-053 |
| chemical formula | BaZr [Si 3 O 9 ] |
|
Mineral class (and possibly department) |
Silicates and germanates - ring silicates (cyclosilicates) |
|
System no. to Strunz and to Dana |
9.CA.05 ( 8th edition : VIII / E.01) 59.01.01.01 |
| Crystallographic Data | |
| Crystal system | hexagonal |
| Crystal class ; symbol | ditrigonal-dipyramidal; 6 m 2 |
| Space group | P 6 c 2 (No. 188) |
| Lattice parameters | a = 6.74 Å ; c = 9.93 Å |
| Formula units | Z = 2 |
| Physical Properties | |
| Mohs hardness | 6 to 6.5 |
| Density (g / cm 3 ) | calculated: 3.82 |
| Cleavage | pyramidal possibly after {10 1 4}; indistinct after {10 1 0} |
| colour | colorless |
| Line color | White |
| transparency | transparent to translucent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n ω = 1.675 to 1.681 n ε = 1.685 to 1.691 |
| Birefringence | δ = 0.010 |
| Optical character | uniaxial positive |
| Other properties | |
| Special features | blue-white fluorescence under short-wave UV light |
Bazirite is a very rare mineral from the mineral class of "silicates and germanates". It crystallizes in the hexagonal crystal system with the chemical composition BaZr [Si 3 O 9 ] and is therefore chemically a barium - zirconium - silicate . Structurally it belongs to the ring silicates (cyclosilicates).
Bazirite is mainly found in the form of irregular grains and granular mineral aggregates , but very rarely also forms individual, prismatic crystals and crystal groups of less than one millimeter in size. The mineral is colorless and transparent, leaves a white line color on the marking board and shows a glass-like sheen on the surface .
Etymology and history
Bazirite was first detected as an independent mineral in 1975 in granite samples that were collected in 1971 and 1972 on the small island of Rockall , about 600 km northwest of Glasgow . The discoverer JR Hawkes named it after the occurring in the chemical compound cations Ba Ministry and Zir conium. It was already known since 1960 that the Rockall granites contain a mineral containing barium and zirconium. A detailed scientific description was finally given in 1978 by BR Young, JR Hawkes, RJ Merriman and MT Styles.
The type material of the mineral is kept in the Natural History Museum in London, Great Britain (Catalog No. MI 36445).
classification
Already in the outdated but still partially in use 8th edition of the mineral classification by Strunz of Bazirit belonged to the mineral class of "silicates and Germanates" and then to the Department of "Ring silicates", where he together with Benitoite , Bobtraillit , Pabstit , Rogermitchellit and Wadeit the "Benitoitgruppe" with the system no. VIII / E.01 .
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), also classifies Bazirit in the "ring silicates" section. This is, however, further subdivided according to the structure of the rings and the possible presence of additional anions , so that the mineral according to its structure and its composition in the subdivision "[Si 3 O 9 ] 6− triple single rings without island-like, complex anions" is to be found, where only together with Benitoit and Pabstit the "Benitoit group" with the system no. 9.CA.05 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the bazirit to the class of "silicates and Germanates" and there in the department of "ring silicates: triple rings" and here, too, it is in the " benitoite group " with the system No. 59.01.01 to be found in the sub-section "Ring silicates: anhydrous triple rings, no other anions".
Crystal structure
Bazirite crystallizes isotypically with benitoite and pabstit in the hexagonal crystal system in the space group P 6 c 2 (space group no. 188) with the lattice parameters a = 6.74 Å and c = 9.93 Å and two formula units per unit cell .
properties
Under short-wave UV light , Bazirit shows a blue-white fluorescence , similar to that of neon-colored highlighters .
Education and Locations
Bazirite forms in the late stage of the crystallization of aegirine - riebeckite - granites and is therefore mainly found on the interfaces between the grains of the granite components. However, it can also arise in granular, celsian-containing rocks near the contact zone with the granite. As Begleitminerale occur depending on the location next to Aegirin, celsian and Riebeckite, you still actinolite , albite , apatite , barite , cristobalite , diopside , Elpidite , Eudialyt , Leukophosphit , magnetite , monazite , pyrochlore , quartz , Taramellit , titanite and xenotime on.
Bazirite is one of the very rare mineral formations, of which only a few samples exist that have been collected at around 10 known sites so far (as of 2015). Its type locality , the remote rocky island Rockall in the North Atlantic, is the only known site in Western Europe to date .
Other previously known localities are the "Mina la Madre Lena" at Tres Pozos in the Mexican state of Baja California Sur , the Khaldzan Buragtag massif in the Altai Mountains in the Mongolian province of Khovd Province , the glacier Darai-Pioz ( Darai-Pioz ) in Alay Mountains in Tajikistan, Šebkovice the Czech Okres Třebíč and several small localities of the Rush Creek - deposit in Fresno County and a lost point in the Baumann prospecting at Dumtah in Tulare County in the US state of California.
See also
literature
- Young BR, Hawkes JR, Merriman RJ, MT Styles: Bazirite, BaZrSi 3 O 9 ; a new mineral from Rockall Island, Inverness-shire, Scotland . In: 'Mineralogical Magazine . tape 42 , March 1978, p. 35–40 ( minersoc.org [PDF; 1.1 MB ; accessed on June 4, 2018]).
Web links
Individual evidence
- ↑ a b c d 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. 595 .
- ↑ a b c d Mindat - Bazirite
- ↑ a b c Webmineral - Bazirite
- ↑ a b c d Bazirite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 61 kB ; accessed on June 4, 2018]).
- ^ Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 704 (first edition: 1891).
- ↑ Find location list for Bazirit in the Mineralienatlas and in Mindat