Aerugite

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Aerugite
Aerugite-198370.jpg
Light to dark green crystal lawn made of aerugite from Johanngeorgenstadt, Erzgebirge, Saxony ( overall size : 1.7 cm × 0.9 cm × 0.8 cm)
General and classification
chemical formula
  • Ni 8.5 (AsO 4 ) 2 As 5+ O 8
  • Ni 8.5 As [6] [O 8 | (AsO 4 ) 2 ]
  • ≈ Ni 9 [O 4 | (AsO 4 ) 3 ]
Mineral class
(and possibly department) 		Phosphates, arsenates and vanadates
System no. to Strunz
and to Dana 		8.BC.15 ( 8th edition : VII / B.09)
05/38/09/01
Crystallographic Data
Crystal system trigonal
Crystal class ; symbol ditrigonal-scalenohedral; 3  2 / m
Space group R 3 m (No. 166)Template: room group / 166
Lattice parameters a  = 5.95  Å ; c  = 27.57 Å
Formula units Z  = 3
Physical Properties
Mohs hardness 4th
Density (g / cm 3 ) measured: 5.85 (7); calculated: 5.772
Cleavage is missing
Break ; Tenacity brittle
colour dark grass green, blue green, light brown
Line color light green to light bluish green
transparency translucent
shine weak glass to diamond luster, resin luster

Aerugit is a very rarely occurring minerals from the mineral class of "phosphates, arsenates, and vanadates" with the chemical composition Ni 8.5 As [6], [O 8 | (AsO 4 ) 2 ] and is therefore chemically seen a nickel - arsenate with additional oxygen ion .

Aerugite crystallizes in the trigonal crystal system , but has so far only been found in the form of fine-grained crystals, coarse masses and crusty coatings up to about two millimeters thick. The translucent mineral is dark grass green to blue green or light brown in color and has a similar light green to light blue green streak color .

Etymology and history

The mineral was first described in 1858 by Carl Wilhelm Bergemann . He discovered it in a sample from the area around Johanngeorgenstadt in the Ore Mountains , which he had received from the mineralogist and mineral dealer Adam August Krantz . He in turn found the sample in a collection bought in 1857 in Schneeberg .

Bergemann described the mineral as an opaque, dark-grass-green, crystalline mass that merges into a dull brown in individual places and appears amorphous there. In addition to some chemical and physical information, Bergemann already gave a very precise chemical composition with the formula Ni 5 As 2 O 10 (calculated from the proportionate oxide compounds). He hesitated, however, to give the new mineral a name because it seemed more convenient to wait until it was found in large quantities.

Its name, which is still valid today, aerugite, was probably given to the mineral in 1869 by the French mineralogist Gilbert Joseph Adam (1795–1881), who lists it in a tabular overview in his publication Tableau Mineralogique . Adam does not provide an explanation for the name, however, and some of the properties listed in the table have been confused with those of xanthiosit , although he referred to Bergemann's descriptions. By William H. Blackburn and William H. Dennen (1997), however, the name is a derivation of the Latin word aeruquo (also aerugo ) for verdigris be based on the color of the mineral.

The type material of the mineral is in the Natural History Museum in London (England) under the catalog no. 32590 and 1907,103 .

classification

In the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the aerugite belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "anhydrous phosphates, with foreign anions F, Cl, O, OH", where he formed the unnamed group VII / B.09 together with Angelellit and Grattarolait .

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 assigns aerugite to the category of “phosphates etc. with additional 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 medium-sized cations; (OH etc.): RO 4  > 1: 1 and <2: 1 “can be found where it is the only member of the unnamed group 8.BC.15 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns aerugite to the class of "phosphates, arsenates and vanadates" and there in the section "anhydrous phosphates etc.". Here he is to be found as the only member of the unnamed group May 38, 2010 within the sub-section “Anhydrous phosphates etc., with various formulas”.

Chemism

According to the last structural analysis carried out by Michael E. Fleet and Jacques Barbier in 1989 , Aerugit has the idealized chemical composition Ni 17 As 6 O 32 (also Ni 8.5 As 3 O 16 ). In the four samples from the Johanngeorgenstadt type locality, however, there were also small amounts of foreign additions of bismuth , cobalt , iron , copper and phosphorus .

Crystal structure

Aerugite crystallizes trigonal in the space group R 3 m (space group no. 166) with the lattice parameters a  = 5.95  Å and c  = 27.57 Å as well as three formula units per unit cell . Template: room group / 166

Education and Locations

Aerugite forms as a secondary mineral in hydrothermal Ni-As-U ore deposits . As Begleitminerale occur depending on the locality, among other native bismuth , bunsenite and / or Xanthiosit on.

Except at its type locality Johanngeorgenstadt was the mineral in Saxony still around the nearby town of Marienberg and about 1.5 km north-west of it on the Abraham stockpile at the shaft 139 (not to be confused with the father Abrahamschacht , bismuth shaft 152) at Lauta be discovered .

The only other site (as of 2018) is in the Ratnapura district on the island of Sri Lanka .

See also

literature

  • C. Bergemann: XXVI. About some nickel ores . In: Journal for Practical Chemistry . tape 75 , 1858, pp. 239–244 ( rruff.info [PDF; 221 kB ; accessed on April 1, 2018]).
  • RJ Davis, MH Hey and AWG Kingsbury: Xanthiosite and Aerugite . In: Mineralogical Magazine . tape 35 , 1965, pp. 72–83 ( minersoc.org [PDF; 2.8 MB ; accessed on April 2, 2018]).
  • Michael E. Fleet and Jacques Barbier: Structure of aerugite (Ni 8.5 As 3 O 16 ) and interrelated arsenate and Germanate structural series . In: Acta Crystallographica Section B . tape 45 , 1989, pp. 201-205 , doi : 10.1107 / S0108768189002727 .
  • 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. 734 .

Web links

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

Individual evidence

  1. ^ IMA / CNMNC List of Mineral Names; November 2017 (PDF 1.67 MB)
  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.  447 .
  3. ^ Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp.  630 (first edition: 1891).
  4. ↑ a b c d e f g Aerugite . 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; 62  kB ; accessed on April 1, 2018]).
  5. ↑ Mindat - Aerugite (English)
  6. ↑ a b C. Bergemann: XXVI. About some nickel ores . In: Journal for Practical Chemistry . tape 75 , 1858, pp. 239–244 ( rruff.info [PDF; 221 kB ; accessed on April 1, 2018]).
  7. ↑ a b Thomas Witzke : The discovery of Aerugit at www.strahl.org
  8. ^ The Mineralogical Record - ADAM, Gilbert-Joseph (1795-1881)
  9. ↑ Langenscheidt Latin-German: Latin-German translation for "aerugo"
  10. ^ Michael E. Fleet and Jacques Barbier: Structure of aerugite (Ni 8.5 As 3 O 16 ) and interrelated arsenate and Germanate structural series . In: Acta Crystallographica Section B . tape 45 , 1989, pp. 201-205 , doi : 10.1107 / S0108768189002727 .
  11. ↑ Find location list for aerugite in the Mineralienatlas and Mindat