Kamchatkit

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Kamchatkit
General and classification
other names

IMA 1987-018

chemical formula
  • KCu 3 O (SO 4 ) 2 Cl
  • KCu 3 [O | Cl | (SO 4 ) 2 ]
  • Cu 3 [O | (SO 4 ) 2 ] + KCl
Mineral class
(and possibly department) 		Sulphates (selenates, tellurates, chromates, molybdates and tungstates)
System no. to Strunz
and to Dana 		7.BC.35
02/30/08/01
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  = 9.74  Å ; b  = 12.86 Å; c  = 7.00 Å
Formula units Z  = 4
Physical Properties
Mohs hardness 3.5
Density (g / cm 3 ) measured: 3.48 (1); calculated: 3.58
Cleavage completely according to {011} and {100}
Break ; Tenacity fragile
colour greenish brown to yellow brown
Line color yellow
transparency transparent
shine Glass gloss
radioactivity hardly detectable
Crystal optics
Refractive indices n α  = 1.695
n β  = 1.718
n γ  = 1.759
Birefringence δ = 0.064
Optical character biaxial positive
Axis angle 2V = 75 ° (measured), 76 ° (calculated)
Other properties
Chemical behavior water soluble, hygroscopic

Kamchatkit is a very seldom occurring mineral from the mineral class of "sulfates (including selenates, tellurates, chromates, molybdates and tungstates)" with the chemical composition KCu 3 O (SO 4 ) 2 Cl or in the crystal chemical structural formula notation KCu 3 [O | Cl | (SO 4 ) 2 ]. Kamchatkit is therefore a potassium - copper - sulfate with additional oxygen and chlorine ions .

Kamchatkit crystallizes in the orthorhombic crystal system and develops long prismatic crystals up to about three millimeters in length with a glass-like sheen on the surfaces. The crystals are transparent and greenish-brown to yellow-brown in color. On the other hand, Kamchatkit leaves a yellow line on the notice board .

Etymology and history

Kamchatkite was discovered in mineral samples from the Tolbatschik volcano , more precisely on its second cinder cone at the “Jadowitaja” fumarole on the Kamchatka peninsula in the Russian Federation Far East . After the mineral was recognized in 1987 by the International Mineralogical Association (IMA), the first description was published in 1988 by LP Vergasova, SK Filatov, YK Serafimova, TV Varaksina, who named it after the peninsula as a region of type locality .

The type material of the mineral is stored in the Mining Institute in Saint Petersburg under the collection no. 1947/1 kept.

classification

Since the Kamchatkit was only recognized as an independent mineral in 1987, it is not yet listed in the 8th edition of the Strunz mineral classification, which has been outdated since 1977 . Only in the Lapis mineral directory , which was revised and updated in 2018 by Stefan Weiß, which is still based on this classic system from Karl Hugo Strunz out of consideration for private collectors and institutional collections , the mineral received the system and mineral number. VI / B.05-30 . In the "Lapis Classification" this represents the class of the "sulphates, chromates, molybdates and tungstates" and then the department of "Anhydrous sulfates, with foreign anions " where Kamchatkit with Alumoklyuchevskit , Chlorothionit , Fedotovit , Klyuchevskit , Piypit and Puninit a forms an independent but unnamed group.

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and was updated by the IMA until 2009, also classifies the Kamchatkit in the category of "Sulphates (selenates, etc.) with additional anions, without H 2 O". However, this is further subdivided according to the relative size of the cations involved , so that the mineral can be found according to its composition in the sub-section "With medium-sized and large cations", where it is the only member of the unnamed group 7.BC.35 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Kamchatkit to the class of "sulfates, chromates, molybdates" (including selenates and tellurates, selenites, tellurites, sulfites) and there in the category of "anhydrous sulfates with hydroxyl or Halogen ”. Here he is the only member of the unnamed group 02/30/08 within the sub-section “Anhydrous sulfates with hydroxyl or halogen with (AB) 2 XO 4 Z q ”.

Chemism

The analysis of the type material samples from Kamchatka consisted of a combination of flame photometry , atomic absorption spectrometry and volume-weight analyzes. This gave an average composition of 48.62% CuO; 0.17% PbO; 0.62% ZnO; 0.20% Na 2 O; 10.48% K 2 O; 6.20% Cl; 33.96% SO 3 , 1.75% H 2 O - and 0.00% H 2 O + (all data in% by weight). After deducting H 2 O and calculating O 2+ for the charge balance, the composition corresponds to the empirical formula (K 1.06 Na 0.03 ) Σ = 1.09 (Cu 2.92 Zn 0.04 ) Σ = 2 , 96 (SO 4 ) 2.03 O 1.04 Cl 0.84 , resulting in KCu 3 (SO 4 ) 2 was idealized OCl.

Crystal structure

Kamchatkit crystallizes orthorhombically in the space group Pna 2 1 (space group no. 33) with the lattice parameters a  = 9.74  Å ; b  = 12.86 Å and c  = 7.00 Å and 4 formula units per unit cell . Template: room group / 33

Crystal structure of Kamchatkit

  • looking parallel to the a-axis

  • looking parallel to the b-axis

  • looking parallel to the c-axis

  • spatial representation in the standard crystallographic orientation

Color table: __ K     __ Cu     __ O     __ S     __ Cl

properties

morphology

Kamchatkit develops long prismatic, rod-shaped crystals with a rectangular or rhombic cross-section that are stretched along the c-axis [001]. The predominant crystal forms are {110}, {100}, {010}, and {001}.

Chemical and physical properties

The mineral dissolves in water and weak acids at a dilution of 1:20 and is also hygroscopic , i.e. it is able to absorb moisture from the surrounding air. Kamchatkit decomposes in the air within a few weeks.

With a Mohs hardness of 3.5, kamchatkite is one of the medium-hard minerals and lies between the reference minerals calcite (3) and fluorite (4) in terms of hardness . Assuming sufficient crystal sizes, Kamchatkit would be easier to scratch with a pocket knife than fluorite .

Education and Locations

Kamchatkit forms as a volcanic sublimation product at temperatures between 120 ° C and 140 ° C. The accompanying minerals included hematite , klyuchevskite , ponomarevite and tolbachite .

Apart from its type locality, the fumarole "Jadowitaja" on Tolbatschik on the Russian Kamchatka Peninsula, the mineral has so far only been found in the former nickel mine near Bolivia in Churchill County of the US state Nevada (as of 2019).

See also

literature

  • LP Vergasova, SK Filatov, YK Serafimova, TV Varaksina: Камчаткит KCu 3 OCl (SO 4 ) 2 - новьій Минерал из вулканических возгонов . In: Zapiski Vsesoyuznogo Mineralogicheskogo Obshchestva . tape 117 , no. 4 , 1988, pp. 459–461 (Russian, rruff.info [PDF; 219 kB ; accessed on November 5, 2019] English title: Kamchatkite KCu 3 OCl (SO 4 ) 2 - a new mineral from volcanic sublimates , brief description in English).
  • John Leslie Jambor , Jacek Puziewicz: New mineral names . In: American Mineralogist . tape 75 , 1990, pp. 1209–1216 (English, rruff.info [PDF; 1.5 MB ; accessed on November 5, 2019]).
  • TV Varaksina, VS Fundamensky, SK Filatov, LP Vergasova: The crystal structure of kamchatkite, a new naturally occuring oxychloride sulphate of potassium and copper . In: Mineralogical Magazine . tape 54 , 1990, pp. 613–616 (English, rruff.info [PDF; 194 kB ; accessed on November 5, 2019]).

Web links

Commons : Kamchatkite  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ a b c Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: September 2019. (PDF 2672 kB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, September 2019, accessed November 5, 2019 .
  2. ↑ a b c d 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 c 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.  375 (English).
  4. ^ A b David Barthelmy: Kamchatkite Mineral Data. In: webmineral.com. Retrieved November 5, 2019 .
  5. ↑ a b c d e f g h Kamchatkite . 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; 68  kB ; accessed on November 5, 2019]).
  6. ↑ a b c d e Kamchatkite. In: mindat.org. Hudson Institute of Mineralogy, accessed November 5, 2019 .
  7. ↑ Catalog of Type Mineral Specimens - K. (PDF 96 kB) In: docs.wixstatic.com. Commission on Museums (IMA), December 12, 2018, accessed November 5, 2019 .
  8. ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed November 5, 2019 .
  9. ↑ John Leslie Jambor , Jacek Puziewicz: New mineral names . In: American Mineralogist . tape  75 , 1990, pp. 1209–1216 (English, rruff.info [PDF; 1.5 MB ; accessed on November 5, 2019]).
  10. ↑ Find location list for Kamchatkit in the Mineralienatlas and Mindat , accessed on November 5, 2019.