Sahlinite

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Sahlinite
General and classification
chemical formula
  • Pb 14 [Cl 4 | O 9 | (AsO 4 ) 2 ]
  • Pb 14 (AsO 4 ) 2 O 9 Cl 4
  • Pb 14 O 9 (AsO 4 ) 2 Cl 4
Mineral class
(and possibly department) 		Phosphates, arsenates and vanadates (formerly halides)
System no. to Strunz
and to Dana 		8.BO.20 ( 8th edition : III / D.10)
41.01.04.01
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  = 12.71  Å ; b  = 22.50 Å; c  = 11.36 Å
β  = 119.0 °
Formula units Z  = 4
Physical Properties
Mohs hardness 2 to 3
Density (g / cm 3 ) measured: 7.38 to 8.00; calculated: 8.096
Cleavage completely after {010}
colour light sulfur yellow, light greenish yellow, yellow to orange
Line color pale yellow
transparency translucent
shine Diamond luster
Crystal optics
Refractive index n  x > 3.3
Optical character biaxial negative
Axis angle 2V = 96.5 ° (measured)

Sahlinite is a very rarely occurring mineral from the mineral class of "phosphates, arsenates and vanadates" with the chemical composition Pb 14 [Cl 4 | O 9 | (AsO 4 ) 2 ] and is therefore chemically a lead - arsenate with additional chlorine - and oxygen - ions and the arsenic analogue to Kombatit .

Sahlinite crystallizes in the monoclinic crystal system , but develops only tiny, flaky crystals up to about two millimeters in size in fibrous or coarse mineral aggregates and crusty coatings. The mineral is translucent and has a diamond-like sheen on the surfaces of the light sulfur-yellow, light greenish-yellow or yellow to orange crystals . Sahlinit leaves a pale yellow line on the whiteboard .

Etymology and history

Carl Sahlin (1915)

Sahlin was first discovered in the Långban mining community in the Swedish province of Värmlands län . It was first described in 1934 by Gregori Aminoff , who named the mineral after the Swedish metallurgist, general director of an ironworks and industrial historian Carl Sahlin ( Carl Andreas Sahlin , 1861–1943). Among other things, he carried out extensive investigations into the history of use of the older Swedish mountain management and was co-founder of three technical-historical museums: the Mine Museum of Falun , the Laxå Bruksmuseum and the Tekniska museet (Technical Museum) in Stockholm .

Sahlenite was already known before the International Mineralogical Association (IMA) was founded and is therefore recognized as a so-called grandfathered mineral as an independent type of mineral.

The type material of the mineral is in the Stockholm Naturhistoriska riksmuseet (literally Natural History Museum ) in Sweden under the catalog no. g22707-08 and in the National Museum of Natural History in Washington, DC in the USA under catalog no. B13892 kept.

classification

In the outdated, but partly still in use, 8th edition of the mineral classification according to Strunz , the sahlinite still belonged to the mineral class of "halides" and there to the department of "oxyhalides", where it together with asisite , blixite , chubutite (rejected by the IMA), Damarait , Ekdemit , Heliophyllit , Kombatit , Mendipite , Mereheadit , Nadorit , Parkinsonit , Penfieldit , Perit , Philolithit , Pinalit , Schwartzembergit , Seeligerit , Sundiusit , Symesit and Thorikosit the "Mendipite-Nadorit group" with the system number. III / D.10 .

The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), assigns sahlinite to the class of "phosphates, arsenates and vanadates" and there in the department of "phosphates, etc." further anions , without H 2 O “. However, 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 according to its composition in the subsection “With exclusively large cations; (OH etc.): RO 4  ≥ 1: 1 "can be found where the" Sahlinit group "with the system no. 8.BO.20 and the only other member Kombatit forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns sahlinite to the class of “phosphates, arsenates and vanadates” and there to the category of “anhydrous phosphates etc., with hydroxyl or halogen”. Here he is also together with Kombatit in the unnamed group 41.01.04 within the subsection “Anhydrous phosphates etc., with hydroxyl or halogen with (A 2+ ) m (XO 4 ) p Z q , with m: p> 4: 1 " to find.

Chemism

The theoretical composition of sahlinite (Pb 14 [Cl 4 | O 9 | (AsO 4 ) 2 ]) consists of 83.73% lead, 4.09% chlorine, 4.33% arsenic and 7.85% oxygen. In the sahlinite samples from the Långban type locality, small additions of around 0.43% carbon dioxide (CO 2 ), 0.46% calcium in the form of CaO and 0.10% water of crystallization (H 2 O) were also found.

Crystal structure

Sahlinite crystallizes isostructural (in the same structure type ) with Kombatite in the monoclinic crystal system in the space group C 2 / c (space group no. 15) with the lattice parameters a  = 12.71  Å ; b  = 22.50 Å; c  = 11.36 Å and β = 119.0 ° and 4 formula units per unit cell . Template: room group / 15

Education and Locations

At its type locality Långban in Sweden, sahlinite was found in a metamorphosed Fe-Mn ore body, where it occurred in paragenesis with dolomite , forsterite , hausmannite and manganhumite . Other previously known sites in Sweden are the Jakobsberg mine near Nordmark and the Harstigen mine near Pajsberg ( Persberg ) in the Filipstad municipality .

In Namibia , sahlinite was found in the stratified hausmannite- barite ores of the underground mine Kombat in the community of Grootfontein (Otjozondjupa), where besides hausmannite and barite it occurs in association with native copper and jacobsite .

Two other documented sites, the Wesley Mine at Westbury on Trym just 5 km north of Bristol and the Torr Works quarry at Cranmore just 5 km east of Shepton Mallet in England , have not yet been confirmed.

use

Due to its rarity, sahlinite is only of interest to collectors.

See also

literature

  • G. Aminoff : Note on a new mineral from Långban (Sahlinite) . In: Geologiska Föreningens i Stockholm Förhandlingar . tape 56 , 1934, pp. 493–494 ( rruff.info [PDF; 53 kB ; accessed on June 5, 2018]).
  • William F. Foshag: New mineral names . In: American Mineralogist . tape 20 , 1935, pp. 314–317 ( rruff.info [PDF; 232 kB ; accessed on June 5, 2018]).
  • Pete J. Dunn, George Y. Chao, Joan J. Fitzpatrick, Richard H. Langley, Michael Fleischer, Janet A. Zilczer: New mineral names . In: American Mineralogist . tape 71 , 1986, pp. 227–232 ( rruff.info [PDF; 602 kB ; accessed on June 5, 2018]).
  • E. Bonaccorsi, M. Pasero: Crystal structure refinement of sahlinite, Pb 14 (AsO 4 ) 2 O 9 Cl 4 . In: Mineralogical Magazine . tape 67 , 2003, p. 15–21 ( rruff.info [PDF; 689 kB ; accessed on June 5, 2018]).
  • John Leslie Jambor , Andrew C. Roberts: New mineral names . In: American Mineralogist . tape 89 , 2004, p. 467–471 ( rruff.info [PDF; 695 kB ; accessed on June 5, 2018]).

Web links

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.  469 .
  2. ↑ a b Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties . 6th completely revised and supplemented edition. Weise, Munich 2014, ISBN 978-3-921656-80-8 .
  3. ↑ a b IMA / CNMNC List of Mineral Names; March 2018 (PDF 1.65 MB; Sahlenite see p. 164)
  4. ↑ a b c d e f Sahlinite . 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; 64  kB ; accessed on June 5, 2018]).
  5. ↑ a b Webmineral - Sahlinite (English)
  6. ^ A b Richard V. Gaines, H. Catherine W. Skinner, Eugene E. Foord, Brian Mason , Abraham Rosenzweig: Dana's New Mineralogy . 8th edition. John Wiley & Sons, New York (et al.) 1997, ISBN 0-471-19310-0 , pp. 816 .
  7. ↑ a b E. Bonaccorsi, M. Pasero: Crystal structure refinement of sahlinite, Pb 14 (AsO 4 ) 2 O 9 Cl 4 . In: Mineralogical Magazine . tape 67 , 2003, p. 15–21 ( rruff.info [PDF; 689 kB ; accessed on June 5, 2018]).
  8. ^ Marie Nisser: Carl A. Sahlin in the Swedish biographical lexicon, Volume 31 (2000–2002), p. 252
  9. ↑ Type mineral catalog of the Naturhistoriska riksmuseet - Sahlinit (g22707-08)
  10. ↑ Find location list for sahlinite at the Mineralienatlas and at Mindat