Seligmannite

from Wikipedia, the free encyclopedia
Seligmannite
Seligmannite, Galena-546339.jpg
Seligmannite crystal lawn on galena from the Palomo Mine, Castrovirreyna Province , Huancavelica, Peru (size 3.4 cm × 3.3 cm)
General and classification
chemical formula
  • PbCuAsS 3
  • PbCu [AsS 3 ]
  • 2 PbS · Cu 2 S · As 2 S 3
Mineral class
(and possibly department)
Sulfides and sulfosalts
System no. to Strunz
and to Dana
2.GA.50 ( 8th edition : II / D.04a)
04/03/03/01
Crystallographic Data
Crystal system orthorhombic
Crystal class ; symbol orthorhombic-pyramidal; mm 2
Space group Pn 2 1 m (No. 31, position 5)Template: room group / 31.5
Lattice parameters a  = 8.08  Å ; b  = 8.74 Å; c  = 7.63 Å
Formula units Z  = 4
Frequent crystal faces {001}
Twinning generally according to {110}, polysynthetic twins possible
Physical Properties
Mohs hardness 2.5 to 3 ( VHN 100 = 168–181)
Density (g / cm 3 ) measured: 5.38; calculated: 5.41
Cleavage very indistinct after {001}, {100} and {010}
Break ; Tenacity clamshell; brittle
colour dark lead gray to black; polished surfaces pink-white
Line color chocolate brown to black purple
transparency opaque (opaque)
shine Metallic luster

Seligmannite is a seldom occurring mineral from the mineral class of " sulfides and sulfosalts " with the chemical composition PbCu [AsS 3 ] and thus, chemically speaking, lead - copper - sulfarsenide .

Seligmannite crystallizes in the orthorhombic crystal system and develops small, isometric or c-axis stretched, short prismatic to tabular crystals of up to 20 millimeters in size. Flat, rhombic-pyramidal crystals and bournonite-like twins were also observed . The mineral, which is opaque in every form , has a metallic sheen on the surfaces of the dark lead-gray to black crystals, which also appear pink-white on polished surfaces . Its line color , on the other hand, is chocolate-brown to black-violet.

Etymology and history

Name giver Gustav Seligmann

Seligmannite was first discovered in the Lengenbach mine in Binntal in the Swiss canton of Valais. It was first described in 1901 by Heinrich Adolph Baumhauer , who named the mineral after the German banker, crystallographer and mineralogist Gustav Seligmann (1849–1920).

The type material of the mineral is in the Natural History Museum in Freiburg im Üechtland (also Friborg ) in Switzerland under the catalog no. B618 (four crystals) and in the Muséum national d'histoire naturelle in Paris (France) under catalog no. 104.1159 (Cotyp) kept.

classification

Already in the outdated 8th edition of the mineral classification according to Strunz , the seligmannite belonged to the mineral class of "sulfides and sulfosalts" and there to the department "complex sulfides (sulfosalts)", where together with bournonite it belongs to the "seligmannite series" with the system no . II / D.04a as a subgroup of the "lead copper spike luster group" (II / D.04).

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 / E.16-10 . In the “Lapis system” this corresponds to the section “Sulphosalts (S: As, Sb, Bi = x)”, whereby within sections II / E.16 to II / E.18 the lead sulfosalts with As / Sb are included x = 3.0 to 2.5 are gathered. Seligmannit also forms an independent but unnamed group here together with Bournonit (as of 2018).

In contrast, the 9th edition of Strunz's mineral systematics , which has been in force since 2001 and was last updated in 2009 by the International Mineralogical Association (IMA) , classifies seligmannite in the newly defined division of "sulfarsenides, sulfantimonides, sulfbismutides". This is also further subdivided according to the structure of the sulfarsenide, antimonide or bismutide complexes, so that the mineral can be found in the sub-section “Island sulfarsenides (Neso sulfarsenides) etc. without additional sulfur (S)” according to its structure is where it forms the unnamed group 2.GA.50 together with bournonite and součekit .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns seligmannite to the class of "sulfides and sulfosalts" and there in the department of "@@@". Here he is named after him " Seligmannitgruppe " with the system no. 03.04.03 within the sub-section “ Sulphosalts with the ratio 3> z / y and the composition (A + ) i (A 2+ ) j [B y C z ], A = metals, B = semi-metals, C = non-metals" Find.

Chemism

The ideal (theoretical) composition of seligmannite (PbCuAsS 3 ) consists of lead (Pb), copper (Cu), arsenic (As) and sulfur (S) with a mass fraction (% by weight) of 46.89% Pb, 14, 38% Cu, 16.96% As and 21.77% S.

The analysis of the type material from the Binntal, on the other hand, showed a slightly different composition of 46.34 to 48.5% by weight Pb, 13.09 to 15.2% by weight Cu, 13.5 to 16.88% by weight % As and 20.6 to 21.73% by weight S and additionally 0.64 to 1.6% by weight antimony (Sb), 0.27% by weight zinc (Zn), 0.11% by weight. -% silver (Ag) and 0.06% by weight iron (Fe).

Due to mixed crystal formation with bournonite (PbCuSbS 3 ), the antimony content measured in natural seligmannite can be traced back to a partial substitution of arsenic.

Crystal structure

Seligmannite crystallizes isotypically with bournonite in the orthorhombic crystal system in the space group Pn 2 1 m (space group no. 31, position 5) with the lattice parameters a  = 8.08  Å ; b  = 8.74 Å and c  = 7.63 Å as well as four formula units per unit cell . Template: room group / 31.5

The crystal structure of Seligmannit consists of 6-fold and 7-fold coordinated Pb polyhedra , AsS 3 - pyramids and CuS 4 - tetrahedra which are joined together by common edges and corners, thereby forming a 3-dimensional network. Within the framework, the CuS 4 tetrahedra are linked in a chain-like manner by shared corners.

Crystal structure of seligmannite
Color table: __ Pb     __ Cu     __ As     __ S

Education and Locations

Small, prismatic seligmannite crystal from the Palomo mine, Castrovirreyna province , Huancavelica, Peru (image width 1 mm)

At its type locality, the Lengenbach mine in Binntal, seligmannite was found in small cavities in dolomite . Baumhauerite , dufrénoysite , pyrite , rathite , sphalerite and tennantite were found here as accompanying minerals . Seligmannite was also discovered in association with Jordanite in the Bleikvassli massive sulphide deposit near Hemnes in the Norwegian province of Nordland .

As a rare mineral formation, Seligmannite could only be detected in a few places, whereby around 80 sites have been documented worldwide (as of 2020). In addition to the Lengenbach mine, the mineral also occurred in Switzerland in a natural dolomite outcrop and in the fall blocks at the nearby Mässerbach and in a dolomite outcrop between Binn and Fäld (all in the Valais Binntal).

The only known site in Germany so far is the Segen Gottes mine with lead-zinc mineralization in the Kobelsberg mine near Wiesloch in Baden-Württemberg , which was operated until 1954 .

In Austria, the mineral (also found previously only on Haidbachgraben Myrthengraben ) near Semmering in Lower Austria, in a plaster - quarry in Moosegg (municipality Scheffau) in Salzburg and in a natural outcrop at Matzenköpfl near Alpbach in Tyrol.

Other locations include Algeria, Argentina, Armenia, Australia, Bolivia, Bulgaria, Chile, China, Finland, France, Greece, Iran, Ireland, Italy, Canada, Croatia, Namibia, North Macedonia, Peru, Romania, Russia, Serbia, Slovakia, Taiwan, the Czech Republic, Ukraine, Hungary and the United States of America.

See also

literature

  • H. Baumhauer : About seligmannite, a new mineral homeomorphic to bournonite from the dolomite of the Binnenthal . In: Session reports of the Royal Prussian Academy of Sciences . tape 1 , 1901, p. 110–117 ( rruff.info [PDF; 702 kB ; accessed on July 30, 2020]).
  • Clifford Frondel : Unit cell and space group of vrbaite (Tl (As, Sb) 3 S 5 ), seligmannite (CuPbAsS 3 ) and samsonite (Ag 4 MnSb 2 S 6 ) . In: American Mineralogist . tape 26 , 1941, pp. 25–28 (English, rruff.info [PDF; 266 kB ; accessed on July 30, 2020]).
  • Y. Takéuchi, N. Haga: On the crystal structures of seligmannite, PbCuAsS3, and related minerals . In: Journal of Crystallography . tape 130 , 1969, p. 254–260 (English, rruff.info [PDF; 313 kB ; accessed on July 30, 2020]).
  • A. Edenharter, W. Mowacki, Y. Takeuchi: Refinement of the crystal structure of bournonite [(SbS 3 ) 2 | Cu (IV) 2 Pb (VII) Pb (VIII) ] and of seligmannite [(AsS 3 ) 2 | Cu ( IV) 2 PB (VII) Pb (VIII) ] . In: Journal of Crystallography . tape 131 , 1970, pp. 397–417 ( rruff.info [PDF; 915 kB ; accessed on July 27, 2020]).
  • Philippe Roth: Minerals first discovered in Switzerland and minerals named after Swiss individuals . 1st edition. Kristallografik Verlag, Achberg 2007, ISBN 3-9807561-8-1 , p. 132-133 .

Web links

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

Individual evidence

  1. 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 July 30, 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.  145 (English, as Seligmanite (misspelling!)).
  3. ^ A b Helmut Schrätze , Karl-Ludwig Weiner : Mineralogie. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp.  296 .
  4. a b c d e f g h i j k Seligmannite . 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; 65  kB ; accessed on July 30, 2020]).
  5. Catalog of Type Mineral Specimens - S. (PDF 143 kB) In: docs.wixstatic.com. Commission on Museums (IMA), December 12, 2018, accessed August 4, 2020 .
  6. 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 .
  7. 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 July 30, 2020 .
  8. Seligmannite. In: Mineralienatlas Lexikon. Stefan Schorn u. a., accessed on July 30, 2020 .
  9. ^ Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp.  475 (first edition: 1891).
  10. Localities for Seligmannite. In: mindat.org. Hudson Institute of Mineralogy, accessed July 30, 2020 .
  11. ^ Grube Segen Gottes, Grubenfeld Kobelsberg, Wiesloch, Rhein-Neckar-Kreis, Karlsruhe district, Baden-Württemberg. In: Mineralienatlas Lexikon. Stefan Schorn u. a., accessed on August 4, 2020 .
  12. Find location list for Seligmannite in the Mineralienatlas and Mindat , accessed on July 30, 2020.