Nagyágit

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Nagyágit
Nagyagite-163939.jpg
Nagyágit from the type locality Nagyág (Săcărâmb), Romania (image width 3 mm)
General and classification
other names
  • Nagyagit (after Haidinger)
  • Nagyagererz or Nagiakererz (after Werner)
  • Leaf ore (after Karsten)
  • Leaf tellurium (after Hausmann)
chemical formula
  • [Pb 3 (Pb, Sb) 3 S 6 ] (Au, Te) 3
  • [Pb (Pb, Sb) S 2 ] [Au, Te]
  • (Au, Te) 3 Pb 3 (Pb, Sb, Bi) 3 S 6
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.HB.20a ( 8th edition : II / D.15)
11/02/10/01
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group P 2 1 / m (No. 11)Template: room group / 11
Lattice parameters a  = 4.22  Å ; b  = 4.18 Å
α  = 15.12 °; β  = 95.4 °
Formula units Z  = 2
Frequent crystal faces {010}
Twinning multiple twins after (001)
Physical Properties
Mohs hardness 1.5
Density (g / cm 3 ) measured: 7.35 to 7.49; calculated: 7.29
Cleavage perfect after {010}, very perfect after {101}
Break ; Tenacity flexible, slightly deformable
colour gray-white, lead-gray to black
Line color grey black
transparency opaque
shine Metallic luster
Other properties
Chemical behavior soluble in nitric acid with precipitation of gold, in aqua regia with separation of silver chloride and sulfur

Nagyagit obsolete as Blättererz , Blättertellur , Nagyiakererz or Nagyakker silver known is a rarely occurring mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the monoclinic crystal system with the chemical composition [Pb 3 (Pb, Sb) 3 S 6 ] (Au, Te) 3 and structurally belongs to the sulfosalts.

Nagyágit is opaque in every form and usually develops gray-white or lead-gray to black crystals with a thin tabular to leafy habit and metallic sheen , but also granular to massive aggregates . Nagyágit often simulates a pseudo orthorhombic to -tetragonal symmetry through multiple twinning .

Etymology and history

As early as 1782, the Austrian chemist and mineralogist Franz Joseph Müller von Reichenstein examined the then still unknown minerals Nagyágite and Sylvanite in the gold ores from the Mariahilf mine near Zlatna (German: Klein Schlatten , Hungarian: Zalatna ) near Sibiu (German: Hermannstadt, Transylvania , Romania ) that contained less gold than expected. He attributed this to the occurrence of a new, previously unknown element, and gave the metallic phase the name metallum problematicum (also aurum problematicum or aurum paradoxum ).

In 1797 Martin Heinrich Klaproth examined the samples from Reichenstein again in Berlin , confirmed his assumption the following year and named the new element tellurium .

Abraham Gottlob Werner introduced the designation Nagiakererz or Nagyakker-Silber in his mineral systematics in 1789 and added to this with the remark: “At the moment I don't know anything more about the Nagyakker-silver than that the Nagyakker-Gold ore is the place of birth, as the name already shows, has in common, is also quite similar to the same, but lighter in color. " Dietrich Ludwig Gustav Karsten initially adopted this name, but changed it in 1800 with the reason:" The generic name in Vienna is leaf ore in some More excellent than the geographical word Nagyakkererz . "

Haidinger finally referred to the mineral in 1845 in his "Handbook of Determining Mineralogy" as Nagyagite, based on its Nagyág (now Săcărâmb ) type locality in the Austrian Empire (now Romania ), which Werner had already mentioned .

At the end of the 20th century, Nagyágit was re-examined as a potential high-temperature superconductor . Only in the course of this research was the crystal structure of Nagyágite finally clarified by mineralogists in Vienna and Salzburg in 1999 .

In older publications, the mineral name can usually be found in the spelling Nagyagit (without acute ), which, however, does not correspond to the specifications for mineral naming of the International Mineralogical Association (IMA), according to which, for example, minerals that were named after a geographical location are taken into account must be that the spelling of the name corresponds to that of the type locality. The inconsistent spelling of their names in many minerals was corrected with the publication “Tidying up Mineral Names: an IMA-CNMNC Scheme for Suffixes, Hyphens and Diacritical marks” in 2008 and the Nagyágit has been spelled internationally since then with the associated acute.

classification

Already in the outdated 8th edition of the mineral classification according to Strunz , the Nagyágite belonged to the mineral class of "sulfides and sulfosalts" and there to the division of "sulfides with [the substance ratio ] M (metal): S (sulfur) <1: 1", where together with Calaverite , Kostovite , Krennerite , Montbrayite and Sylvanite, the group of "Gold-Silver-Telluride" with the system no. II / C.04 formed.

In the Lapis mineral directory according to Stefan Weiß, which, out of consideration for private collectors and institutional collections, is still based on this old form of Karl Hugo Strunz's system , the mineral was given the system and mineral number. II / D.15-20 . In the "Lapis Classification" This also corresponds to the department "sulfides with [molar ratio] Metal: S, Se, Te <1: 1" where Nagyagit with Buckhornit, Jaszczakit , Jonassonit , Montbrayit and Museumit an independent but unnamed Group forms (as of 2018).

The 9th edition of Strunz's mineral systematics, which has been valid since 2001 and was updated by the IMA until 2009, classifies the Nagyágit in the newly defined section of “Sulphosalts with SnS as a model”. This is further subdivided according to the predominant metals in the compound, so that the mineral can be found according to its composition in the sub-section "With Cu, Ag, Fe, Sn and Pb", where it is the only member of the unnamed group 2.HB. 20a forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Nagyágit to the class of "sulfides and sulfosalts" and there to the department of "sulfide minerals". Here he is the only member of the unnamed group “02.11.10” within the subdivision “Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 2: 3”.

Crystal structure

Nagyágit crystallizes monoclinically in the space group P 2 1 / m with the lattice parameters a  = 4.22  Å ; b  = 4.18 Å; c  = 15.12 Å and β = 95.4 ° as well as two formula units per unit cell .

properties

Nagyágite is easily meltable in front of the soldering tube on carbon, with yellow lead (II) oxide and white telluric acid settling some distance away . After prolonged blowing, a grain of gold is finally excreted. When dissolved in nitric acid , Nagyágit deposits gold, and in aqua regia lead (II) chloride and sulfur .

Education and Locations

Nagyagit found in gold and tellurium hydrothermal courses . In the type locality at Săcărâmb it will meet up with altaite , petzite , Stützit , Sylvanit , Tellurantimon , Coloradoite , krennerite , dignified arsenic and gold , Proustite , rhodochrosite , arsenopyrite , sphalerite and tetrahedrite . Another paragenesis with calaverite , gold, tellurobismuthite , altaite, galena , pyrite can be found e.g. B. in the Bohuliby mine in the Czech Republic.

As a rare mineral formation, Nagyágit could only be proven at a few sites, whereby so far (as of 2015) around 70 sites are known. In addition to its type locality Săcărâmb, the mineral occurred in Romania at Baia de Arieș in Alba County and in the “Musariu” copper-gold deposit near Brad in Hunedoara County.

The only known site in Austria so far is the Stüblbau pit near Schellgaden in the Salzburg municipality of Muhr and the only known site in Switzerland so far is Gondo in the canton of Valais.

Other sites include the "El Sid Mine" near Koptos in Egypt; the Farallón Negro Mine in the Argentine department of Belén ; the Armenian province of Kotayk ; Western Australia (Australia); the “Chelopech Au-Cu Mine” near Panagyurishte in Bulgaria; the "El Hueso Mine" near Diego de Almagro in the Chilean Región de Atacama ; the "Emperor Mine" near Vatukoula on the Fiji Islands; the "Kawazu Mine" near Shimoda in Japan; the "Olive Mabel claim" ( British Columbia ) and the "Huronian Mine" ( Ontario ) in Canada; the "Sahuayacan Mine" in the Mexican state of Chihuahua ; the "Sylvia Mine" near Thames in New Zealand; Bohemia in the Czech Republic; in the former Clogau mine near Bontddu in Wales (UK) and in several regions of the United States (USA).

use

Due to its rarity, Nagyágit is of little importance as gold ore.

See also

literature

  • Yves Moëlo, Emil Makovicky , Nadejda N. Mozgova, John L. Jambor , Nigel Cook, Allan Pring, Werner Paar, Ernest H. Nickel , Stephan Graeser, Sven Karup-Møller, Tonči Balic-Žunic, William G. Mumme, Filippo Vurro , Dan Topa, Luca Bindi, Klaus Bente, Masaaki Shimizu: Sufosalt systematics: a review. Report of the sulfosalt sub-committee of the IMA Commission on Ore Mineralogy . In: European Journal of Mineralogy . tape 20 , 2008, p. 7–46 ( ima-mineralogy.org [PDF; 1.7 MB ; accessed on August 16, 2020] Nagyágit from p. 18).
  • H. Effenberger et al .: Toward the crystal structure of nagyagite, [Pb (Pb, Sb) S 2 ] [(Au, Te)] . In: American Mineralogist . tape 84 , 1999, pp. 669–676 (English, [1] [PDF; 134 kB ; accessed on August 16, 2020]).
  • John Leslie Jambor , Andrew C. Roberts: New Mineral Names . In: American Mineralogist . tape 80 , 1995, pp. 184–188 (English, minsocam.org [PDF; 486 kB ; accessed on August 16, 2020]).
  • 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. 303 .

Web links

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

Individual evidence

  1. ↑ a b Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: July 2020. (PDF; 2.44 MB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, July 2020, accessed August 16, 2020 .
  2. ↑ 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.  124 .
  3. ↑ a b Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
  4. ↑ a b c d e Nagyágite . 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; 66  kB ; accessed on August 16, 2020]).
  5. ^ Nagyágite. In: mindat.org. Hudson Institute of Mineralogy, accessed August 16, 2020 .
  6. ^ Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp.  454 (first edition: 1891).
  7. ↑ a b Hans Lüschen: The names of the stones. The mineral kingdom in the mirror of language . 2nd Edition. Ott Verlag, Thun 1979, ISBN 3-7225-6265-1 , p. 189-190 .
  8. ^ Dietrich Ludwig Gustavus Karsten: Museum Leskeanum, regnum animale (regnum minerale) quod ordine systematico . tape 2 . Müller, Leipzig 1789 ( limited preview in Google book search [accessed on August 16, 2020]).
  9. ^ Wilhelm Ritter von Haidinger : Handbook of determining mineralogy . Verlag Braumüller & Seidel, Vienna 1845, p.  563-570 ( rruff.info [PDF; 451 kB ; accessed on August 16, 2020]).
  10. ↑ Ernest H. Nickel , Joel D. Grice: The IMA Commission on New Minerals and Minerala Names: Procedures and Guidelines on Mineral Nomenclature . In: The Canadian Mineralogist . tape  36 , 1998, pp. 8th ff . ( cnmnc.main.jp [PDF; 316 kB ; accessed on August 16, 2020]).
  11. ^ Ernst AJ Burke: Tidying up Mineral Names: an IMA-CNMNC Scheme for Suffixes, Hyphens and Diacritical marks . In: Mineralogical Record . tape 39 , no. 2 , 2008, p. 131–135 (English, cnmnc.main.jp [PDF; 2.4 MB ; accessed on August 16, 2020]).
  12. ↑ a b Ernest H. Nickel , Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF; 1.82 MB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed August 16, 2020 .
  13. ^ Johann Gottlob von Kurr , Gustav Adolf Kenngott (revision of the 3rd edition): von Kurr's mineral kingdom in pictures . 3. Edition. Published by JF Schreiber, Eßlingen 1878, p.  38 ( /blog.mineralium.com [PDF; 3.7 MB ; accessed on August 16, 2020]).
  14. ↑ Localities for Nagyágite. In: mindat.org. Hudson Institute of Mineralogy, accessed August 16, 2020 .
  15. ↑ List of localities for Nagyágit in the Mineralienatlas and Mindat , accessed on August 16, 2020.