Kemmlitzite

from Wikipedia, the free encyclopedia
Kemmlitzite
General and classification
chemical formula SrAl 3 [(OH) 6 | SO 4 | AsO 4 ]
Mineral class
(and possibly department) 		Phosphates, arsenates and vanadates
System no. to Strunz
and to Dana 		8.BL.05 ( 8th edition : VII / B.35)
04/43/01/07
Crystallographic Data
Crystal system trigonal
Crystal class ; symbol ditrigonal-scalenohedral; 3  2 / m
Space group R 3 m (No. 166)Template: room group / 166
Lattice parameters a  = 7.07  Å ; c  = 16.51 Å
Formula units Z  = 3
Physical Properties
Mohs hardness 5.5
Density (g / cm 3 ) measured: 3.63; calculated: 3.601
Cleavage bad after {0001}
colour colorless, gray-brown, light brown
Line color White
transparency transparent to translucent
shine Glass gloss
radioactivity weak (243 Bq / g)
Crystal optics
Refractive indices n ω  = 1.701
n ε  = 1.707
Birefringence δ = 0.006
Optical character uniaxial positive

Kemmlitzit is a mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the trigonal crystal system with the chemical composition SrAl 3 [(OH) 6 | SO 4 | AsO 4 ], so chemically speaking it is a strontium - aluminum arsenate with additional sulfate - ([SO 4 ] 2− ) and hydroxide ions (OH - ).

Natural Kemmlitzite samples can contain various foreign additions such as cerium and other rare earth metals as well as calcium, magnesium, iron, silicon and phosphorus.

Etymology and history

Was first discovered in Kemmlitzit Kemmlitz in Nordsachsen and 1969. Jaroslav Hak, Zdenek Johan, M. Kvaček and Werner Liebscher, the mineral after its type locality designated.

classification

In the outdated, but still in use 8th edition of the mineral classification according to Strunz , Kemmlitzit belonged to the class of "phosphates, arsenates and vanadates" and there to the department of "anhydrous phosphates, with foreign anions F, Cl, O, OH", where it belongs together with Beudantit , Corkit , Gallobeudantit , Hidalgoit , Hinsdalit , Orpheit , Schlossmacherit , Svanbergit and Woodhouseit the "Beudantitgruppe" with the system no. VII / B.35 .

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 Kemmlitzite to the category of “phosphates, etc. with additional anions; without H 2 O “. This is further subdivided according to the relative size of the cations involved and the molar ratio of the additional anions (OH etc.) to the phosphate, arsenate or vanadate complex (RO 4 ), so that the mineral can be classified according to its composition in the sub-section “With medium-sized and large cations; (OH etc.): RO 4  = 3: 1 “can be found, where together with Beudantite, Corkite, Gallobeudantite, Hidalgoite, Hinsdalite, Orpheit, Schlossmacherite, Svanbergite, Weilerit and Woodhouseit the“ Beudantite group ”with the system no. 8.BL.05 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Kemmlitzite to the class of "phosphates, arsenates and vanadates" and there in the department of "phosphates". Here it is together with Beudantite, Corkite, Gallobeudantite, Hidalgoite, Hinsdalite, Orpheit, Svanbergite, Weilerite and Woodhouseit in the Beudantite group 43.04.01 within the subdivision of " Compound phosphates etc., (anhydrous compound anions with hydroxyl or halogen) " .

Crystal structure

Kemmlitzite crystallizes trigonal in the space group R 3 m (space group no. 166) with the lattice parameters a  = 7.02  Å and c  = 16.51 Å as well as 3 formula units per unit cell . Template: room group / 166

Education and Locations

The type locality of Kemmlitzit is a kaolin pit near Kemmlitz in northern Saxony in a kaolinized quartz porphyry complex . Anatase , apatite , kaolinite and zircon were found here as accompanying minerals .

In addition to its type locality, the mineral was also found in Germany in the Louise mine near Greimerath in the Rhineland-Palatinate district of Trier-Saarburg and in a limestone quarry near the municipality of Rüdersdorf near Berlin in Brandenburg.

The only confirmed site in Switzerland so far is the Falotta mine in the former municipality of Tinizong-Rona (now Surses ) in the canton of Graubünden.

In addition, Kemmlitzit is so far (as of 2017) only known from Vestřev and Podsedice in the Czech region of Bohemia and from the Flambeau mine near Ladysmith in Rusk County in the US state of Wisconsin.

See also

literature

  • J. Hak, Z. Johan, M. Kvacek, W. Liebscher: Kemmlitzite, a new mineral of the woodhouseite group . In: New yearbook for mineralogy, monthly books . 1969, p. 201-212 .
  • Michael Fleischer : New Mineral Names . In: The American Mineralogist . tape 55 , no. 1-2 , 1970, pp. 317–323 ( minsocam.org [PDF; 530 kB ; accessed on June 3, 2017]).
  • Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 604 (first edition: 1891).

Web links

Individual evidence

  1. ↑ a b c d e 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.  462 .
  2. ↑ a b Kemmlitzite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy . Mineralogical Society of America, 2001 ( PDF 65 kB ).
  3. ↑ a b Kemmlitzite Mineral Data. In: webmineral.com. Retrieved April 8, 2016 .
  4. ↑ a b Kemmlitzite. In: mindat.org. Retrieved April 12, 2016 .
  5. ↑ Thomas Witzke : discoverer of minerals from Saxony, Saxony-Anhalt and Thuringia (including first mentions and names). Retrieved June 3, 2017 .
  6. ↑ J. Hak, Z. Johan, M. Kvacek, W. Liebscher: Kemmlitzite, a new mineral of the woodhouseite group . In: New yearbook for mineralogy, monthly books . 1969, p. 201-212 .
  7. ↑ Find location list for Kemmlitzite at the Mineralienatlas and at Mindat