Cervantite

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Cervantite
Cervantite-109568.jpg
Macro shot of colorless, needle-like cervantite crystals from Zlatá Baňa , Slanské vrchy , Eastern Slovakia (field of view 3 mm)
General and classification
other names
  • Antimony ocher
  • Yellow antimony ore
chemical formula
  • Sb 3+ Sb 5+ O 4
  • Sb 2 O 4
Mineral class
(and possibly department) 		Oxides and hydroxides
System no. to Strunz
and to Dana 		4.DE.30 ( 8th edition : IV / D.25)
04.04.16.01
Crystallographic Data
Crystal system orthorhombic
Crystal class ; symbol orthorhombic-pyramidal; mm 2
Space group Pna 2 1 (No. 33)Template: room group / 33
Lattice parameters a  = 5.46  Å ; b  = 4.81 Å; c  = 11.79 Å
Formula units Z  = 4
Physical Properties
Mohs hardness 4.5
Density (g / cm 3 ) measured:> 6.5; calculated: 6.64
Cleavage completely after {001}; clearly after {100}
colour colorless to white, yellow to reddish white; colorless in transmitted light
Line color light yellow to white
transparency translucent
shine Greasy sheen, earthy matt
Crystal optics
Refractive indices n α  = 2.000
n γ  = 2.100
Birefringence δ = 0.100
Optical character biaxial
Other properties
Chemical behavior Easily soluble in hydrochloric acid

Cervantit is a rather seldom occurring mineral from the mineral class of "oxides and hydroxides" with the chemical composition Sb 3+ Sb 5+ O 4 (also Sb 2 O 4 for simplicity ) and is therefore chemically antimony (III, V) oxide .

Cervantite crystallizes in the orthorhombic crystal system , but develops only microscopic, needle-like crystals from a few tenths to a maximum of one millimeter in size, which usually come together to form radial to spherical mineral aggregates . It is therefore found almost exclusively in the form of granular to earthy aggregates or crusty coatings and efflorescence. As an oxidation product of antimony sulfide, it also occurs as a pseudomorphism from cervantite to stibnite ( antimonite ) or various antimony sulfo salts.

In its pure form, Cervantit is colorless and transparent. However, due to multiple refraction due to lattice construction defects or polycrystalline formation, it can also appear white and take on a reddish-white to yellow color due to foreign admixtures. Its streak color is light yellow to white. The crystal surfaces have a fat-like sheen , but Cervantit in aggregate form has a rather earthy matt appearance.

Etymology and history

Cervantit was first described in 1850 by James Dwight Dana , who reported on Armand Dufrénoy 's analysis of an ocher from Cervantes in the Spanish province of Lugo (Community of Galicia ). According to Dufrénoy, the ocher contained 67.50% antimony (Sb), 16.85% oxygen (O), 11.45% calcium oxide (CaO) and 1.5% iron (Fe). A crusty coating on antimony ores from Chazelles in Auvergne had the same composition. According to Dana, the mineral was anhydrous and had the formula SbO 4 .

After a thorough investigation of Antimonocker 1952, Charles J. Vitaliano and Brian Mason saw the cervantite as identical to stibiconite (Sb 3+ Sb 5+ 2 O 6 (OH)), a cubic crystallizing mineral with a pyrochlore structure and the general formula (Sb 3 + , Ca) ySb 5+ 2-x (O, OH, H 2 O) 6-7 with 0> x> 1 and y ≈ 1. According to Vitaliano and Mason, cervantite would only be a synonym for stibiconite, assuming that anhydrous Sb 2 O 4 does not occur as a mineral.

In 1962 the formula for cervantite with Sb 2 O 4 was redefined by W. Gründer, H. Pätzold and Hugo Strunz with the proposal to restore its status as an independent mineral type. Although the type material from Cervantes was no longer available for comparison, the new definition was recognized by the Commission on new Minerals, Nomenclature and Classification (CNMNC) of the International Mineralogical Association (IMA).

classification

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the cervantite belonged to the mineral class of "oxides and hydroxides" and there to the department of "oxides with a metal: oxygen ratio = 1: 2 (MO 2 and related compounds) "where he along with Bismutocolumbit , Bismutotantalit , Chiluit , Klinocervantit , Stibiocolumbit and Stibiotantalit the" Stibiotantalit group "with the system no. IV / D.25 .

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the IMA, also classifies Cervantit in the oxides division with a molar ratio of “metal: oxygen = 1: 2 and comparable”. However, this is further subdivided according to the relative size of the cations involved and the crystal structure , so that the mineral is classified in the sub-section “With medium-sized cations; With various polyhedra ”can be found where, together with stibiotantalite, the“ stibiotantalite-cervantite group ”with the system no. 4.DE.30 and the other members Bismutocolumbit, Bismutotantalit, Klinocervantit and Stibiocolumbit forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns cervantite to the class of "oxides and hydroxides" and there in the "oxides" category. Here it can be found together with Klinocervantit in the unnamed group 04.04.16 within the sub-section “Simple oxides with a cation charge of 4+ (AO 2 )”.

Crystal structure

Cervantit crystallizes orthorhombically in the space group Pna 2 1 (space group no. 33) with the lattice parameters a  = 5.46  Å ; b  = 4.81 Å and c  = 11.79 Å as well as 4 formula units per unit cell . Template: room group / 33

Modifications and varieties

The compound Sb 3+ Sb 5+ O 4 is dimorphic and occurs in nature in addition to the orthorhombic crystallizing cervantite as monoclinic crystallizing clinocervantite .

The term antimony ocher for yellowish, very soft and friable weathering products on stibnite, among others, was coined by Karl Caesar von Leonhard in 1821 . By August Breithaupt also still the synonymous term was spit glass ocher following the synonym spit glass introduced for stibnite. Antimony ocher can easily be melted and reduced to a small metal ball in front of the soldering tube with a lively surge. With further heating, this evaporates and releases a garlic-like odor. A white precipitate forms on coal and borax.

Through further investigation antimony ocher was identified as mixture of mainly two minerals, the 1932 by François Sulpice Beudant discovered Stibiconit (originally Stibiconise , modified in 1862 by George Jarvis Brush ) and in 1850 by Dufrenoy and Dana discovered Cervantit.

Education and Locations

Crystal aggregate of a pseudomorphism from cervantite to stibnite from the Gallos Mine, Sierra de Santa Rosa, Municipio de Mazapil , Zacatecas , Mexico (size: 6.7 cm × 5.8 cm)
Quartz crystal with inclusions of stibnite (black) and cervantite (yellow) from the Trinity Mountains, Lovelock , Pershing County, Nevada (size: 4.4 cm × 4.4 cm × 4.1 cm)

As a typical secondary mineral, cervantite is formed by oxidation from stibnite and other antimony minerals.

As a rather rare mineral formation, cervantite can sometimes be abundant at various sites, but overall it is not very common. Around 300 sites for Cervantit have been documented so far. In addition to its type locality Cervantes in the province of Lugo (Galicia), where in addition to stibnite and cervantite also valentinite was found, the mineral was also found in Spain in the Matilde mine (Victoria mine, Velez-Malaga) near La Vinuela in the province of Málaga (Andalusia ), the Mina de la Nazarena near Almuradiel in the province of Ciudad Real (Castile-La Mancha) and at the Collada Verde in the municipality of Ripollès in the province of Girona (Catalonia).

In Germany, Cervantit has so far been known mainly from Baden-Württemberg, more precisely from the mining area around Sulzburg such as the antimony mine Schweizergrund and the Schnelling mine as well as the Clara mine near Oberwolfach and the Segen Gottes mine near Wiesloch . The mineral was also found in several places in North Rhine-Westphalia such as the antimony-producing Caspari colliery and the Bautenberg iron ore mine in the Arnsberg district, as well as the Birkengang zinc smelter (also Friedrich-Wilhelm ) and the copper smelter near Kall in the Cologne district; in Rhineland-Palatinate such as the Hope mine (also called Spes mine ) near Martinsknipp , the Georg mine in the Willroth community and the Neue Hope mine in the Bleialf community and in Saxony such as the Sonnenwirbel mine and Hohlewein near Brand-Erbisdorf , the Neue Hope mine God's at Bräunsdorf (Oberschöna) and the Glückssonne mine at Mobendorf . Individual finds were also known from fire wood in the Bavarian community of Goldkronach , from the five books Mosis mine near Sankt Andreasberg in Lower Saxony and the Graf Jost-Christian-Zeche near Wolfsberg (Sangerhausen) in Saxony-Anhalt.

In Austria, Cervantit has so far been found in an antimony mine near Stadtschlaining in Burgenland; in the former marble mining Bürgergiltsteinbruch near Friesach- Olsa and the antimony mines on Rabantberg near Oberdrauburg and near Hapatnik / Klein St. Veit in the municipality of Völkermarkt in Carinthia; in an antimony deposit at Maltern in the Lower Austrian municipality of Hochneukirchen-Gschaidt as well as in the Obernberg Valley and near Rattenberg in Tyrol.

In Switzerland, the mineral has so far only been found in an antimony mineralization near a hammer forge on the Magliasina river and the La Monda mine in the Ticino municipality of Aranno .

Other locations are in Australia, Bolivia, China, Italy, Mexico, New Zealand, Slovakia, Hungary, the United Kingdom (UK) and the United States of America (USA).

See also

literature

  • JD Dana: Cervantite, in A System of Mineralogy . 3. Edition. George P. Putnam, New York, London 1850, p. 417 (English, rruff.info [PDF; 79 kB ; accessed on October 9, 2018]).
  • K. Dihlström: About the construction of the true antimony tetroxide and the isomorphic stibiotantalite, SbTaO4 . In: Journal of Inorganic and General Chemistry . tape 239 , 1938, pp. 57–64 (English, rruff.info [PDF; 401 kB ; accessed on October 9, 2018]).
  • Brian Mason and Charles J. Vitaliano: The Mineralogy of the Antimony Oxides and Antimonates . In: Mineralogical Magazine . tape 30 , 1953, pp. 100–112 (English, minersoc.org [PDF; 581 kB ; accessed on October 10, 2018]).
  • W. founder, H. Pätzold, H. Strunz: Sb 2 O 4 as a mineral (cervantite) . In: New yearbook for mineralogy, monthly books . tape 2 , 1962, pp. 93-98 .
  • Michael Fleischer : New Mineral Names . In: American Mineralogist . tape 47 , 1962, pp. 1216–1223 (English, rruff.info [PDF; 618 kB ; accessed on October 9, 2018]).
  • Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 543 (first edition: 1891).

Web links

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

Individual evidence

  1. ^ A b Karl Caesar von Leonhard : Handbuch der Oryktognosie . Mohr and Winter, Heidelberg 1821, p.  159 ( limited preview in Google Book search).
  2. ↑ Mineral Atlas : Yellow Antimony Ore
  3. ↑ 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.  216 (English).
  4. ↑ a b c d IMA / CNMNC List of Mineral Names; March 2018 (PDF 1.65 MB)
  5. ↑ a b c 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. 251 .
  6. ↑ Webmineral - Cervantite (English)
  7. ↑ a b c d e Cervantite . 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; 67  kB ; accessed on October 8, 2018]).
  8. ↑ a b c Mindat - Cervantite (English)
  9. ↑ a b JD Dana: Cervantite, in A System of Mineralogy . 3. Edition. George P. Putnam, New York, London 1850, p. 417 (English, rruff.info [PDF; 79 kB ; accessed on October 8, 2018]).
  10. ^ Charles J. Vitaliano, Brian Mason: Stibiconite and Cervantite . In: American Mineralogist . tape 37 , no. 11-12 , 1952, pp. 982–999 (English, minsocam.org [PDF; 1,2 MB ; accessed on October 9, 2018]).
  11. ↑ 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. 173, 195 .
  12. ^ François-Sulpice Beudant: Traité élémentaire de minéralogie . 2nd Edition. tape 2 . Chez Verdière, Paris 1832, p. 616 (French, limited preview in Google Book search).
  13. ↑ Mindat - Number of localities for Cervantit (English)
  14. ↑ Find location list for Cervantit in the Mineralienatlas and Mindat