Zabuyelit

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Zabuyelit
Zabuyelite.jpg
White zabuyelite crystal aggregate from the Tanco Mine, Bernic Lake, Manitoba , Canada
General and classification
other names

IMA 1985-018

chemical formula Li 2 [CO 3 ]
Mineral class
(and possibly department) 		Carbonates and nitrates
System no. to Strunz
and to Dana 		5.AA.05
14.01.15.02
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group C 2 / c (No. 15)Template: room group / 15
Lattice parameters a  = 8.36  Å ; b  = 4.97 Å; c  = 6.20 Å
β  = 114.6 °
Twinning after {100}
Physical Properties
Mohs hardness 3
Density (g / cm 3 ) measured: 2.09 (1); calculated: 2.10
Cleavage perfect after {100}, good after {011}
Break ; Tenacity brittle
colour colorless
Line color White
transparency transparent
shine Glass gloss
Crystal optics
Refractive indices n α  = 1.429
n β  = 1.567
n γ  = 1.574
Birefringence δ = 0.146
Optical character biaxial negative
Axis angle 2V = 25 ° (measured), 22 ° (calculated)
Other properties
Chemical behavior Easily soluble in hot water

Zabuyelit is a very rarely occurring mineral from the mineral class of "carbonates and nitrates" with the chemical composition Li 2 [CO 3 ] and thus, chemically speaking, lithium carbonate .

Zabuyelit crystallizes in the monoclinic crystal system and develops prismatic crystals with pyramidal ends with a length in the range of a few micrometers . However, crystals up to about 1.2 mm in size were also observed. It is mostly found in the form of inclusions in halite or spodumene .

The transparent and colorless mineral has a glass-like sheen on the surface . With a Mohs hardness of 3, zabuyelite is one of the medium-hard minerals and, if the size is appropriate, it could be scratched with a copper coin, similar to the reference mineral calcite .

Etymology and history

Lithium carbonate had been known in synthetic form for a long time. Among other things, its morphological-crystallographic and optical constants were described by François Ernest Mallard as early as 1892 .

The natural formation of lithium carbonate as a mineral was first discovered at Chabyêr Caka (also Zabuye Salt Lake ) in Zhongba, a district in the Tibet Autonomous Region in China. The first description was in 1978 by M. Zheng and W. Liu, who named the mineral after its type locality .

The type material of the mineral is kept in the Geological Museum of Beijing in China.

classification

Since the zabuyelite was discovered after 1985 and recognized as an independent mineral, it is not listed in the 8th edition of the mineral classification according to Strunz, which was last updated in 1982 . Only in the “Lapis Mineral Directory”, which was last updated in 2018, which is still based on the classic system of Karl Hugo Strunz out of consideration for private collectors and institutional collections , the mineral received the system no. V / B.01-10 . The mineral would have been classified in the section “Anhydrous carbonates [CO 3 ] 2− without foreign anions ”.

The 9th edition of Strunz's mineral systematics, which has been in force since 2001 and is used by the International Mineralogical Association (IMA), assigns zabuyelite to the class of “carbonates and nitrates” and there to the category of “carbonates without additional anions; without H 2 O “. This is further subdivided according to the affiliation of the cations involved to certain element groups , so that the mineral can be found according to its composition in the sub-section " Alkali carbonates", where it is the only member of the unnamed group 5.AA.05 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the zabuyelite to the class of "carbonates, nitrates and borates" and there in the department of "anhydrous carbonates". Here it can be found together with sodium in the unnamed group 01/14/06 within the sub-section “Anhydrous carbonates with simple formula A + CO 3 ”.

Chemism

In chemically pure form, zabuyelite (Li 2 [CO 3 ]) consists of 18.79% lithium (Li), 16.25% carbon (C) and 64.96% oxygen (O).

The analyzes of the mineral samples from its type locality on the Zabuye salt lake also revealed minor foreign additions of sulfur, nitrogen, boron, iron, manganese, magnesium, calcium, sodium, potassium and chlorine.

Crystal structure

Zabuyelite crystallizes monoclinically in the space group C 2 / c (space group no. 15) with the lattice parameters a  = 8.36  Å ; b  = 4.97 Å; c  = 6.20 Å and β = 114.6 ° and 4 formula units per unit cell . Template: room group / 15

Education and Locations

Zabuyelite generally forms in salt lakes and is mainly found as inclusions in other salt minerals such as halite , gaylussite and northupite , but also in pegmatites as inclusions in spodumene , which are accordingly regarded as accompanying minerals of zabuyelith.

Zabuyelith is one of the very rare mineral formations that so far (as of 2018) has only been known in a few samples from less than 10 localities. In China, in addition to its type locality Chabyêr Caka in Zhongba, the mineral was also found in a carbonate salt lake in Damxung County, which is also part of the Tibetan Autonomous Region, and in the albite and spodumene- containing pegmatite dykes of the Jiajika mine near Kangding in the Chinese province of Sichuan .

Other previously known sites are the spodumene-containing pegmatites from the Tanco opencast mine (Tanco Mine, Bernic Lake Mine) on Lake Bernic (Bernic Lake) near Lac du Bonnet in the Canadian province of Manitoba , and the Muiâne pegmatites near Alto Ligonha in the province Zambezia in Mozambique, the Bikita pegmatite near the place of the same name in the Masvingo province and the Kamativi open pit mine ( pegmatites containing tin and tantalite ) near Dete in the Matabeleland North province in Zimbabwe, and the Foote mine (Foote Lithium Co. ) in the Kings Mountain District of Cleveland County of North Carolina.

See also

literature

  • H. Effenberger, J. Zemann: Refinement of the crystal structure of lithium carbonate, Li 2 CO 3 . In: Journal of Crystallography . tape 150 , 1979, pp. 133–138 ( rruff.info [PDF; 268 kB ; accessed on December 14, 2018]).
  • Mianping Zheng, Wengao Liu: A new Li-mineral - zabuyelite . In: Acta Mineralogica Sinica . tape 7 , 1987, pp. 221-226 .
  • John Leslie Jambor , Edward S. Grew: New mineral names . In: American Mineralogist . tape 75 , 1990, pp. 240–246 (English, rruff.info [PDF; 694 kB ; accessed on December 14, 2018]).

Web links

Commons : Zabuyelite  - collection of images, videos and audio files

Individual evidence

  1. ↑ 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.  284 (English).
  2. ↑ a b Webmineral - Zabuyelite (English)
  3. ↑ a b c d e f g h i Zabuyelite . 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 December 10, 2018]).
  4. ↑ a b 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 .
  5. ↑ a b c d e Mindat - Zabuyelite (English)
  6. ↑ John Leslie Jambor , Edward S. Grew: New mineral names . In: American Mineralogist . tape  75 , 1990, pp. 240–246 (English, rruff.info [PDF; 694 kB ; accessed on December 14, 2018]).
  7. ↑ H. Effenberger, J. Zemann: Refinement of the crystal structure of lithium carbonate, Li 2 CO 3 . In: Journal of Crystallography . tape 150 , 1979, pp. 133–138 ( rruff.info [PDF; 268 kB ; accessed on December 14, 2018]).
  8. ↑ Find location list for zabuyelite at the Mineralienatlas and at Mindat