Kogarkoite

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Kogarkoite
Kogarkoite - Poudrette quarry, Mont Saint-Hilaire, Quebec, Canada.jpg
Kogarkoite from the “Poudrette” mine, Mont Saint-Hilaire, Canada
General and classification
other names

IMA 1970-038

chemical formula Na 3 [F | SO 4 ]
Mineral class
(and possibly department) 		Sulfates
System no. to Strunz
and to Dana 		7.BD.15 ( 8th edition : VI / B.12)
01/30/06/01
Similar minerals Burkeite , calcite , fluorite , halite , trona
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Room group (no.) P 2 1 / m (No. 11)
Lattice parameters a  = 18.07  Å ; b  = 6.96 Å; c  = 11.44 Å
β  = 107.7 °
Formula units Z  = 12
Twinning Rotary twins {102}, pseudohexagonal {0001}
Physical Properties
Mohs hardness 3.5
Density (g / cm 3 ) 2.66 to 2.68
Cleavage not defined
Break ; Tenacity not defined
colour colorless, white, pale blue
Line color White
transparency transparent to translucent
shine Glass gloss
Crystal optics
Refractive indices n α  = 1.439
n β  = 1.439
n γ  = 11.442
Birefringence δ = 0.003
Optical character biaxial positive
Other properties
Special features fluorescence

Kogarkoite is a rarely occurring mineral from the mineral class of " sulfates ". It crystallizes in the monoclinic crystal system with the chemical composition Na 3 [F | SO 4 ] and develops mostly granular or earthy aggregates, but also pseudo-hexagonal crystals , which can be either colorless or white to pale blue in color.


Etymology and history

Found for the first time was kogarkoite 1973 in "Lake Umbozero mine" on the mountain Alluaiw in Lovozero massif ( Ловозеро ) on the peninsula Kola in Russia and described by Adolf Pabst and WN Sharp that the mineral after the Russian geochemist and Petro Login Lija Nikolaevna Kogarko named .

classification

In the old (8th edition) and new systematics of minerals according to Strunz (9th edition) , the kogarkoite belongs to the division of "anhydrous sulfates with foreign anions ". The new Strunz'sche mineral classification, however, subdivides more precisely according to the size of the cations involved and the mineral is therefore correspondingly in the sub-section “With only large cations”, where it is the only member of the unnamed group 7.BD.15 .

The common in the English language classification of minerals by Dana also assigns the kogarkoite in the class of sulfates, there, however, in the Department of " sulfates with hydroxyl or halogen, and the general composition (AB) Water outdoor m (XO 4 ) p Z q , besides, is m: p> 2: 1 “, where he is also the only member of the unnamed group 30.1.6 .

Education and Locations

Kogarkoite is created by resublimation from the steam of hot springs .

So far (as of 2010) Kogarkoite has been detected at around 10 sites worldwide, including at Mont Saint-Hilaire in the Canadian region of Montérégie , at the Suswa volcano in the Kenyan province of Rift Valley and at several hot springs in Chaffee County (Colorado) and Colfax County, New Mexico in the United States .

Crystal structure

Kogarkoite crystallizes monoclinically in the space group P 2 1 / m with the lattice parameters a  = 18.07  Å ; b  = 6.96 Å; c  = 11.44 Å and β = 107.7 ° and 12 formula units per unit cell .

See also

Individual evidence

  1. ↑ Webmineral - Kogarkoite (English)
  2. ^ A b Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 377 .
  3. ↑ Handbook of Mineralogy - Kogarkoite (English, PDF 65.3 kB)
  4. ↑ a b Kogarkoite at mindat.org (engl.)
  5. ^ Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 377 .

Web links

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