Camérolait

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Camérolait
Mineraly.sk - camerolait.jpg
Camérolait efflorescence on matrix from Piesky, Špania Dolina , Starohorské vrchy, Slovakia
General and classification
other names

IMA 1990-036

chemical formula
  • Cu 6 Al 3 (OH) 18 (H 2 O) 2 [Sb (OH) 6 ] (SO 4 )
  • Cu 6 Al 3 [(OH) 18 | Sb (OH) 6 | SO 4 ] • 2H 2 O
  • Cu 4 Al 2 [(OH) 10 | CO 3 | (HSbO 4 , SO 4 )] • 2H 2 O
Mineral class
(and possibly department) 		Sulphates (selenates, tellurates, chromates, molybdates and tungstates)
System no. to Strunz
and to Dana 		7.DE.75
03/44/11/01
Crystallographic Data
Crystal system triclinic
Crystal class ; symbol triklin-pedial; 1
Space group P 1 (No. 1)Template: room group / 1
Lattice parameters a  = 6.3310 (13)  Å ; b  = 2.9130 (6) Å; c  = 10.727 (2) Å
α  = 93.77 (3) °; β  = 96.34 (3) °; γ  = 79.03 (3) °
Formula units Z  = 1/3
Frequent crystal faces {100}, {001}
Physical Properties
Mohs hardness Please complete!
Density (g / cm 3 ) measured: 3.1 (1); calculated: 2.96
Cleavage good after {100} and {001}
Break ; Tenacity fibrous; brittle
colour blue green
Line color light green
transparency transparent
shine Silky gloss
Crystal optics
Refractive indices n α  = 1.626
n β  = 1.646
n γ  = 1.682
Birefringence δ = 0.056
Optical character biaxial positive
Axis angle 2V = 75 ° to 77 ° (measured), 76 ° (calculated)
Pleochroism Visible:
α = colorless
β = light green
γ = blue-green

Camérolaite is a rarely occurring mineral from the mineral class of "sulfates (selenates, tellurates, chromates, molybdates and tungstates)" with the chemical composition Cu 6 Al 3 [(OH) 18 | Sb (OH) 6 | SO 4 ] · 2H 2 O and therefore, from a chemical point of view, a water-containing copper - aluminum - sulfate with additional antimony and hydroxide ions .

Camérolaite crystallizes in the triclinic crystal system and is mostly found in the form of tufted or radial-radial mineral aggregates made of fibrous to needle-like crystals up to about two millimeters in size. The light blue to blue-green crystals are transparent, however, due to its predominant occurrence in aggregate form, the mineral appears more translucent to opaque. The surfaces of the mineral aggregates have a silk-like sheen .

Etymology and history

Camérolait was first discovered by Michel Camérola in a former copper and lead mine (now a museum) at Cap Garonne in the municipality of Le Pradet (Provence-Alpes-Côte d'Azur region) on the French Mediterranean coast. It was first described in 1991 by Halil Sarp and Pierre Perroud (* 1943), who named the mineral after its discoverer.

In the first description by Sarp and Perroud as well as in older publications, the mineral name is partly in the spelling Camerolait (without acute above the e), which does not, however, correspond to the specifications for mineral naming of the IMA, for example for minerals that were named after a person , it must be ensured that the spelling of the name is used (the only exceptions are spaces and capital letters, which are removed from the mineral name). The inconsistent spelling of their names for many minerals was first corrected in the 2008 publication "Tidying up Mineral Names: an IMA-CNMNC Scheme for Suffixes, Hyphens and Diacritical marks" and made up for other minerals in later years. For the Camérolait, among others, the spelling was corrected in 2015 in Newsletter 28 under IMA no. 15-E and has since been used internationally in the spelling with the associated acute.

The type material of the mineral is in the Muséum d'histoire naturelle de la Ville de Genève in Geneva (Switzerland) under the catalog no. 435/84 kept.

classification

Camérolait is not yet listed in the outdated, but partly still in use, 8th edition of the mineral classification according to Strunz . Only in the “Lapis mineral directory” last updated in 2018, which is still based on this form of system numbering out of consideration for private collectors and institutional collections, did the mineral receive the system and mineral number. IV / D.8-35 .

The 9th edition of Strunz's mineral systematics, valid since 2001 and used by the International Mineralogical Association (IMA), assigns Camérolaite to the class of "sulfates (selenates, tellurates, chromates, molybdates and wolframates)" and there in the department of " Sulphates (selenates etc.) with additional anions, with H 2 O “. However, this is further subdivided according to the relative size of the cations involved and the crystal structure, so that the mineral can be classified in the sub-section “With only medium-sized cations; unclassified ”can be found, where it is the only member of the unnamed group 7.DE.75 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Camérolait to the class of "phosphates, arsenates and vanadates" and there to the "antimonates" category. Here he is the only member of the unnamed group 44.03.11 within the sub-section “Antimonates with different formulas”.

Crystal structure

Camérolaite crystallizes triclinically in the space group P 1 (space group no. 1) with the lattice parameters a  = 6.3310 (13)  Å ; b  = 2.9130 (6) Å; c  = 10.727 (2) Å; α = 93.77 (3) °; β = 96.34 (3) ° and γ = 79.03 (3) ° as well as 1/3 formula units per unit cell . Template: room group / 1

Education and Locations

Camérolaite forms secondarily in the oxidation zone of polymetallic deposits . As a rare mineral formation, Camérolait could only be detected at a few sites, with 14 sites (as of 2019) being documented, all of which are within Europe .

At its type locality on Cap Garonne in the municipality of Le Pradet belonging to the Provence-Alpes-Côte d'Azur region , the mineral was found in association with cyanotrichite , malachite , parnauite and quartz in Triassic sandstone and conglomerates . In addition, Camérolait appeared in France in the limestone and dolomite pit Tistoulet near Padern and in the vicinity of the municipality of Ceilhes-et-Rocozels in the Occitania region .

In Germany, the mineral has so far only occurred in Baden-Württemberg in the Maria Theresia mine near Grunern / Kropbach and in the Clara mine near Oberwolfach in the Freiburg district, as well as in the Neubulach mining district and the Dorothea mine near Freudenstadt in the Karlsruhe district.

In Austria, Camérolait was discovered on the old mining dumps on Mallestiger Mittagskogel near Finkenstein on Faaker See in Carinthia and in a former test mine on Dürrkogel near Veitsch in Mürz Valley in Styria.

The only known site in Switzerland so far is Saint-Luc in the Val d'Anniviers of the canton of Valais, where the mineral was found together with azurite , brochantite , chalcophyllite and mimetesite in the former ore mines Mine de Gosan and Mine des Moulins .

Other locations are in Italy, Portugal, Slovakia and Spain.

See also

literature

  • Halil Sarp, Pierre Perroud: Camerolaite Cu 4 Al 2 [HSbO 4 , SO4] (OH) 10 (CO 3 ) .2H 2 O, a new mineral from Cap Garonne mine, Var, France . In: New Yearbook for Mineralogy - Treatises . tape November 11 , 1991, pp. 481–486 (English, PDF version available at archive-ouverte.unige.ch [accessed on January 11, 2019]).
  • SJ Mills, Andrew G. Christy, Cédric Schnyder, Georges Favreau, JR Price: The crystal structure of camerolaite and structural variation in the cyanotrichite family of merotypes . In: Mineralogical Magazine . tape 78 , 2014, p. 1527–1552 , doi : 10.1180 / minmag.2014.078.7.02 (English).

Web links

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

Individual evidence

  1. ↑ a b c d IMA / CNMNC List of Mineral Names; November 2018 (PDF 1.7 MB)
  2. ↑ a b c 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 .
  3. ^ A b 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.  405 (English).
  4. ^ A b SJ Mills, Andrew G. Christy, Cédric Schnyder, Georges Favreau, JR Price: The crystal structure of camerolaite and structural variation in the cyanotrichite family of merotypes . In: Mineralogical Magazine . tape 78 , 2014, p. 1527–1552 , doi : 10.1180 / minmag.2014.078.7.02 (English).
  5. ↑ a b c Camérolaite . 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 January 11, 2019]).
  6. ↑ 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. 975 .
  7. ↑ a b c d e f Camérolaite. In: mindat.org. Hudson Institute of Mineralogy, accessed January 11, 2019 .
  8. ^ 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. 194 .
  9. ^ 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 , Volume 36 (1998); PDF 328 kB , from p. 8
  10. ^ 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 ( cnmnc.main.jp [PDF; 2.4 MB ; accessed on May 2, 2020]).
  11. ↑ Ulf Hålenius, Frédéric Hatert, Marco Pasero, Stuart J. Mills: IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) - Newsletter 28 . In: Mineralogical Magazine . tape 79 , no. 7 , 2015, p. 1859–1864 (English, cnmnc.main.jp [PDF; 80 kB ; accessed on January 20, 2019]).
  12. ↑ Halil Sarp, Pierre Perroud: Camerolaite Cu 4 Al 2 [HSbO 4 , SO4] (OH) 10 (CO 3 ) 2H 2 O, a new mineral from Cap Garonne mine, Var, France . In: New Yearbook for Mineralogy - Treatises . tape November 11 , 1991, pp. 481–486 (English, PDF version available at archive-ouverte.unige.ch [accessed on January 11, 2019]).
  13. ↑ a b List of locations for Camérolaite in the Mineralienatlas and Mindat