Löweit

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Löweit
Loweite-95022.jpg
Yellow lion from the "Le Cetine di Cotorniano Mine", Chiusdino , Tuscany, Italy (field of view: 3 mm)
General and classification
other names
  • Lœwide
  • Loewit
chemical formula Na 12 Mg 7 [SO 4 ] 13  · 15H 2 O
Mineral class
(and possibly department) 		Sulphates, Selenates, Tellurates, Chromates, Molybdates and Wolframates
System no. to Strunz
and to Dana 		7.CC.45 ( 8th edition : VI / C.17)
04/29/03/01
Crystallographic Data
Crystal system trigonal
Crystal class ; symbol trigonal-rhombohedral; 3
Space group R 3 (No. 148)Template: room group / 148
Lattice parameters a  = 18.86  Å ; c  = 13.40 Å
Formula units Z  = 3
Physical Properties
Mohs hardness 2.5 to 3
Density (g / cm 3 ) measured: 2.36 to 2.42; calculated: 2.35
Cleavage not yet observed
Break ; Tenacity shell-like
colour colorless, reddish yellow
Line color White
transparency transparent to translucent
shine Glass gloss
Crystal optics
Refractive indices n ω  = 1.490
n ε  = 1.471
Birefringence δ = 0.019
Optical character uniaxial negative
Other properties
Chemical behavior soluble in water, slightly bitter taste

Löweit (also Lœweit or Loewit ) is a rarely occurring mineral from the mineral class of " sulfates ( and relatives )". It crystallizes in the trigonal crystal system with the composition Na 12 Mg 7 [SO 4 ] 13  · 15H 2 O, so from a chemical point of view it is a water-containing sodium - magnesium sulfate.

So far, Löweit could only be found in the form of efflorescence and crusts or irregularly formed crystal grains and granular masses. In its pure form, Löweit is colorless and transparent. However, through the addition of iron oxide, it can also take on a reddish yellow color, with the transparency decreasing accordingly.

Etymology and history

The Löweit was first discovered in Bad Ischler Salzberg in Upper Austria and described in 1846 by Wilhelm von Haidinger , who named the mineral after the Austrian chemist and general coin tester from Vienna Alexander Löwe (1808–1895).

classification

In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the Löweit belonged to the mineral class of "sulfates, selenates , tellurates , chromates , molybdates and tungstates " and there to the department of "water-containing sulfates without foreign anions", where it was classified as the only member formed the unnamed group VI / C.17 .

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 assigns the Löweit to the class of "sulfates (selenates, tellurates, chromates, molybdates and wolframates)" and there in the department of "Sulphates (selenates etc.) without additional anions, with H 2 O". However, this division is further subdivided according to the relative size of the cations involved , so that the mineral can be found according to its composition in the sub-division "With medium-sized and large cations", where it is the only member of the unnamed group 7.CC.45 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Löweit to the class of "sulfates, chromates and molybdates" and there in the department of "water-containing acids and sulfates". Here he is to be found as the only member in the unnamed group 04/29/03 within the sub-section “ Hydrous acids and sulfates with (A + ) 2 B n (XO 4 ) p × x (H 2 O) ”.

Crystal structure

Löweit crystallizes trigonal in the space group R 3 (space group no. 148) with the lattice parameters a  = 18.86  Å and c  = 13.40 Å as well as 3 formula units per unit cell . Template: room group / 148

properties

Löweit is water-soluble and has a slightly bitter taste.

Education and Locations

Löweit usually forms in marine salt deposits , but can also arise as a sublimation product from volcanic gases. The accompanying minerals include anhydrite , aphthitalite , blödite , epsomite , gypsum , hexahydrite , kieserite , langbeinite , mirabilite , pentahydrite , starkeyite , thénardite and vanthoffite .

As a rare mineral formation, Löweit could so far (as of 2012) only be proven at a few sites, with around 20 sites being known to date. In addition to its type locality in Bad Ischler Salzberg, the mineral also appeared in a salt mine near Hallstatt in Upper Austria . Other localities in Austria include the rock salt - deposit at Dürrnberg in Salzburg and the salt mine in Altaussee and gypsum - and anhydrite -Lagerstätte "curtain wall" at Admont in Styria.

In Germany, Löweit was previously in the Neuhof-Ellers potash plant , on Himmelsberg near Giesel (Neuhof) , in the Wintershall potash plant and in the Hattorf potash plant near Philippsthal in Hesse; found in the “Berlepsch” mine near Staßfurt in Saxony-Anhalt and near Merkers in Thuringia.

Other locations include Jianghan , Mangnai and Qakilik in China; the Icelandic island of Surtsey ; Kłodawa in Greater Poland Voivodeship and “Soda Lake” in Carrizo Plain National Monument , California , “West Salt Creek” in Mesa County in Colorado and near Carlsbad in New Mexico in the United States of America.

See also

literature

Web links

Commons : Löweit  - Collection of pictures, videos and audio files

Individual evidence

  1. ↑ a b c d e 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.  390 .
  2. ↑ Webmineral - Löeite
  3. ^ A b John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols: Löweit. In: Handbook of Mineralogy, Mineralogical Society of America. 2001. ( PDF 63.8 kB )
  4. ↑ a b c d Mindat - Löweit
  5. ↑ Mineralienatlas: Löweit
  6. ↑ Mindat - Number of localities for Löweit