Luzonite

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Luzonite
Luzonite-Enargite-Pyrite-117726.jpg
Luzonite on enargite from the "Chinkuahshih Mine", Ruifang , New Taipei ( total size of the step : 6.2 × 3.5 × 1.8 cm)
General and classification
chemical formula Cu 3 AsS 4
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.KA.10 ( 8th edition : II / C.06)
02/03/02/01
Crystallographic Data
Crystal system tetragonal
Crystal class ; symbol tetragonal-scalenohedral; 4 2 m
Space group I 4 2 m (No. 121)Template: room group / 121
Lattice parameters a  = 5.33  Å ; c  = 10.57 Å
Formula units Z  = 2
Physical Properties
Mohs hardness 3.5
Density (g / cm 3 ) measured: 4.38; calculated: 4.53
Cleavage good after {101}, clearly after {100}
colour dark reddish steel gray; turning purple
Line color black
transparency opaque
shine Metallic gloss to matt

Luzonite is a rather rare mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the tetragonal crystal system with the composition Cu 3 AsS 4 , and is thus chemically seen a copper - Sulfarsenat .

Luzonite is opaque in every form and rarely develops well-formed crystals . It is mostly found closely interwoven with enargite in the form of coarse-grained to fine-grained or massive mineral aggregates from dark pink to brown in color with black streak color . Fresh samples initially have a metallic sheen , but then become matt as the weathering progresses.

With famatinite (Cu 3 SbS 4 ), luzonite forms a mixed crystal row .

Etymology and history

Albin Weisbach reached in 1866 by the mining engineer Simon in the possession of some unusual Enargite stages, where the Enargitkristalle on a shiny metallic mineral with a color similar to that of Rotnickelkies ( Nickelin ) or fresh bornite ( bornite sat). However, he initially thought it was a mineral belonging to the “gravel” and did not investigate it further. However, after other mineralogists received similar levels in 1868, in 1869 Bergrath Fritzsche determined copper, arsenic and sulfur as the main components after a qualitative analysis and finally Alfred Wilhelm Stelzner in his treatise on the Enargite passages of the Famatina Mountains in Argentina via a strange, shiny metallic one and red-gray mineral reported, Weisbach also let his colleague Clemens Winkler analyze his grades in more detail. It turned out that the unknown mineral had the same composition as enargite, but had a different crystal structure, i.e. the compound was dimorphic.

Weisbach and Winkler called the new mineral, which was first discovered by Simon on the copper veins of the "Lepanto mine" near Mankayan on the Philippine island of Luzon , as Luzonite , based on its type locality .

classification

Already in the now outdated, but still common 8th edition of the mineral classification according to Strunz , the luzonite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "sulfides with the molar ratio of metal: sulfur, selenium, tellurium = 1: 1", where together with barquillite , briartite , černýite , famatinite , ferrokësterite , hocartite , kësterite , kuramite , permingeatite , petrukite , pirquitasite , rhodostannite , sakuraiite , stannite , toyohaite and velikite the " stannite group " with the system no. II / C.06 formed.

The 9th edition of Strunz's mineral systematics, which has been in force since 2001 and is used by the International Mineralogical Association (IMA), also assigns luzonite to the class of "sulfides and sulfosalts", but in the newly defined section of " sulfarsenates ". In addition, the sulfarsenates are further subdivided depending on whether the compound is built up via (As, Sb) S4 tetrahedra or with additional sulfur. According to its composition, the mineral can therefore be found in the sub-section “Sulpharsenates with (As, Sb) S 4 tetrahedra”, where the “luzonite group” with the system no. 2.KA.10 and the other members barquillite, briartite, famatinite and permingeatite.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , also assigns luzonite to the class of "sulfides and sulfosalts", but there in the department of "sulfosalts". Here he is also the namesake of the "Luzonitgruppe" with the system no. 03.02.02 and the other members famatinite and permingeatite within the subsection “ sulfosalts with the ratio z / y = 4 and the composition (A + ) i (A 2+ ) j [B y C z ], A = metals, B = Semimetals, C = non-metals ”.

Crystal structure

Luzonite crystallizes tetragonally in the space group I 4 2 m (space group no. 121) with the lattice parameters a  = 5.33  Å and c  = 10.57 Å as well as 2 formula units per unit cell . Template: room group / 121

Modifications and varieties

The compound Cu 3 AsS 4 is dimorphic and, in addition to the tetragonally crystallizing luzonite, also occurs as orthorhombically crystallizing enargite .

Education and Locations

Luzonite and pyrite from the "Chinkuahshih Mine", Ruifang , New Taipei

Luzonit forms in copper, arsenic and antimony-rich, low to moderate hydrothermal - veins . In addition to enargite, it occurs in association with many other sulphides such as bismuthinite , chalcopyrite , colusite , covelline , marcasite , pyrite , sphalerite , stannoidite , tetrahedrite and tennantite , various silver sulpho salts, the sulphates alunite and barite , which are also mostly present Quartz as well as solid silver and gold .

As a rather seldom occurring mineral formation, luzonite can in part be abundant at different sites, but overall it is not very common. So far (as of 2012) around 160 sites are known worldwide. In addition to its type locality "Lepanto Mine" on Luzon, Luzonite was found in the Philippines in an outcrop near Tampakan on Mindanao.

The " Quiruvilca Mine" in the province of Santiago de Chuco ( La Libertad ) in Peru, where crystals of up to 4 cm in size were found, is known for its extraordinary luzonite finds .

In Germany the mineral could be found in several places in the Black Forest in Baden-Württemberg such as B. at Wittichen and the well-known Clara mine . In addition, it also occurred on Hohenstein near Lautertal (Odenwald) in Hesse, in the Lüderich mine and the slag dump near Genna / Lethmathe in North Rhine-Westphalia, in the Reich Geschiebe mine near Imsbach in Rhineland-Palatinate and at the Arweiler quarry near Reimsbach in Saarland on.

In Austria, luzonite has so far mainly been found in the vicinity of the Tyrolean communities of Brixlegg and Rattenberg , but also occurred in the Schwarzleograben near Hütten / Leogang in Salzburg and in the Haidbachgraben near Semmering in Lower Austria.

Other locations include Argentina, Armenia, Azerbaijan, Bolivia, Bulgaria, Chile, Fiji, France, Greece, Indonesia, Italy, Japan, Kazakhstan, Malaysia, Macedonia, Mexico, Namibia, Papua New Guinea, Poland, Romania, Russia, Slovakia, Taiwan, the Czech Republic, Tunisia, Turkey, Hungary, Uzbekistan, the United Kingdom (Great Britain) and the United States of America (USA).

See also

literature

Web links

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

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.  79 (English).
  2. ↑ David Barthelmy: Luzonite MineralData. In: webmineral.com. Retrieved June 20, 2019 .
  3. ↑ a b c d Luzonite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 (English, handbookofmineralogy.org [PDF; 62  kB ; accessed on June 20, 2019]).
  4. ↑ a b A. Weisbach: Luzonite . In: Gustav Tschermak (Hrsg.): Mineralogische Mittheilungen . Wilhelm Braumüller University Publishing House , Vienna 1874, p. 257–258 ( rruff.info [PDF; 223 kB ; accessed on June 20, 2019]).
  5. ↑ Luzonite. In: mindat.org. Hudson Institute of Mineralogy, accessed June 20, 2019 .
  6. ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia (=  Dörfler Natur ). Edition Dörfler im Nebel-Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 28 .
  7. ↑ Luzonite. In: mindat.org. Hudson Institute of Mineralogy, accessed June 20, 2019 .