Långbanit
| Långbanit | |
|---|---|
 |
|
| General and classification | |
| chemical formula |
|
|
Mineral class (and possibly department) |
Silicates and germanates - island silicates (nesosilicates) |
|
System no. to Strunz and to Dana |
9.AG.10 ( 8th edition : VIII / B.09) March 44, April 01 |
| Crystallographic Data | |
| Crystal system | trigonal |
| Crystal class ; symbol | ditrigonal-pyramidal; 3 m |
| Room group (no.) | P 31 m (No. 157) |
| Lattice parameters | a = 11.563 (2) Å ; c = 11.100 (2) Å |
| Formula units | Z = 3 |
| Physical Properties | |
| Mohs hardness | 6.5 |
| Density (g / cm 3 ) | measured: 4.92 to 4.94; calculated: 4.97 |
| Cleavage | good after {0001}, secretions after {0001} also possible |
| Break ; Tenacity | clamshell; brittle |
| colour | iron black |
| Line color | dark reddish brown |
| transparency | opaque |
| shine | strong metallic luster |
| Crystal optics | |
| Refractive indices |
n ω = 2.360 n ε = 2.310 |
| Birefringence | δ = 0.050 |
| Optical character | uniaxial negative |
Långbanit is a very rare mineral from the mineral class of " silicates and germanates ". It crystallizes in the trigonal crystal system with the idealized chemical composition Mn 2+ 4 Mn 3+ 9 Sb 5+ [O 16 | (SiO 4 ) 2 ], so it is a manganese - antimony - silicate with additional oxygen ions . Structurally it belongs to the island silicates ( nesosilicates ).
Since part of the manganese in naturally formed Långbanites can be replaced ( substituted ) by calcium or iron , the formula is occasionally also denoted with (Mn 2+ , Ca) 4 (Mn 3+ , Fe 3+ ) 9 Sb 5+ [O 16 | (SiO 4 ) 2 ], whereby the elements indicated in the round brackets can represent each other in the formula, but are always in the same proportion to the other constituents of the mineral.
Långbanit is generally opaque ( opaque ) and developed tabular or short to long prismatic along striped crystals to about one centimeter length with a strong, metallic luster on the black iron surfaces. Långbanit leaves a dark reddish-brown line on the marking board . With a Mohs hardness of 6.5, Långbanite is somewhat harder than the reference mineral orthoclase .
Special properties
Before the soldering tube , Långbanit just becomes matt without melting. It is only sparingly soluble in hydrochloric acid.
Etymology and history
Långbanit was first discovered near the former mining community Långban in the Swedish province of Värmlands län and described in 1877 by Gustaf Flink (also Gustav Flink , 1849–1931)
classification
Already in the outdated, but partly still in use 8th edition of the mineral systematics according to Strunz , the Långbanite belonged to the mineral class of "silicates and germanates" and there to the department of "island silicates with non-tetrahedral anions (Neso-subsilicates)", where it together with Braunit the "Braunit-Långbanit-Gruppe" with the system no. VIII / B.09 and the other members Abswurmbachit , Franciscanit , Katoptrit , Neltnerit , Örebroit , Welinit , Yeatmanit and Zoltaiit .
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 classifies Långbanit in the “island silicates” department. However, this is further subdivided according to the possible presence of additional anions and the coordination of the cations involved , so that the mineral is classified in the sub-section “Island silicates with additional anions; Cations in mostly [6] er and> [6] er coordination ”can be found, where it forms the unnamed group 9.AG.10 as the only member .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Långbanit to the class of "phosphates, arsenates and vanadates" and there in the department of " antimonates ". Here he is to be found as the only member in the unnamed group 44.03.04 within the sub-section “Antimonates with different formulas”.
Education and Locations
Långbanite forms in crystalline limestones , manganese-rich skarns and metamorphosed manganese deposits , where it occurs, among other things, in paragenesis with manganese-rich aegirine , braunite , hausmannite , hedyphan , magnetite , rhodonite and Richterite .
In addition to its type locality Långban, the mineral also appeared in Sweden in the “Sjögruvan Mine” near Grythyttan in the municipality of Hällefors and the “Man Mine” in the “Nyberg” ore field near Lindesberg .
Other previously known sites are the “Gozaisho Mine” near Iwaki on the Japanese island of Honshū, the manganese deposit “Brandsnuten” near Botnedal in the Norwegian municipality of Tokke and the “Fianel” mine near Ausserferrera in the Swiss canton of Graubünden.
Crystal structure
Långbanite crystallizes trigonal in the space group P 31 m (space group no. 157) with the lattice parameters a = 11.563 (2) Å and c = 11.100 (2) Å as well as three formula units per unit cell .
See also
literature
- Gust. Fast: About Långbanit, a new mineral from Långbanshyttan in Wermland, Sweden. In: Journal for Crystallography and Mineralogy. Volume 13, 1888, pp. 1-8. ( PDF 379 kB )
- Robert Lee Crane: A Study of the Crystal Structure of Långbanite. Ohio State University, 1969.
- Helmut Schrätze, Karl-Ludwig Weiner: Mineralogy. A textbook on a systematic basis . de Gruyter, Berlin / New York 1981, ISBN 3-11-006823-0 .
- Hans Jürgen Rösler : Textbook of Mineralogy . 4th, revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p. 491 .
- G. Giuseppetti, F. Mazzi, C. Tadini: The crystal structure of monoclinic langbanite: (Mn, Ca, Fe, Mg) 2+ 4 (Mn, Fe) 3+ 9 Sb 5+ [O 16 (SiO 4 ) 2 ]. In: New Yearbook for Mineralogy. MONTHS, 1991, pp. 193-211.
- Paul Brian Moore, Pradip K. Sen Gupta, Yvon Le Page: The remarkable langbanite structure type: crystal structure, chemical crystallography, and relation to some other cation close-packed structures. In: American Mineralogist. Volume 76, 1991, pp. 1408-1425. ( PDF 1.99 MB )
Web links
Individual evidence
- ↑ a b IMA / CNMNC List of Mineral Names; October 2013 (PDF 1.5 MB)
- ^ 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. 553 .
- ^ A b c Paul Brian Moore, Pradip K. Sen Gupta, Yvon Le Page: The remarkable langbanite structure type: crystal structure, chemical crystallography, and relation to some other cation close-packed structures. In: American Mineralogist. Volume 76, 1991, pp. 1408-1425. ( PDF 1.99 MB )
- ↑ a b Långbanite. In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America. 2001. ( PDF 72.1 kB )
- ^ Mindat - Långbanite
- ^ Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke , Stuttgart 1978, ISBN 3-432-82986-8 (first edition: 1891).
- ^ Project Runeberg: Nordisk familjebok - Flinder's river - Flintporslin (Swedish)
- ↑ The Mineralogical Record - Gustav Flink (English)
- ↑ List of localities for Långbanit in the Mineralienatlas and Mindat