Tazieffit

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Tazieffit
Tazieffite - Mutnovsky volcano, Kamchatka, Russia (Color SEM) .jpg
Electron microscope image with black, needle-like Tazieffit crystals from Mutnowski , Kamchatka , Russia (image width 700 μm)
General and classification
other names

IMA 2008-012

chemical formula
  • Pb 20 Cd 2 (As, Bi) 22 S 50 Cl 10
  • Pb 10 Cd (As, Bi) 11 S 25 Cl 5
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.JB
03.08.01.04
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group C 2 / c (No. 15)Template: room group / 15
Lattice parameters a  = 8.3520 (17)  Å ; b  = 45.5920 (92) Å; c  = 27.2610 (55) Å
β  = 98.84 (3) °
Formula units Z  = 4
Physical Properties
Mohs hardness Please complete!
Density (g / cm 3 ) calculated: 6.07
Cleavage no
Break ; Tenacity brittle
colour silver gray with a tinge of magenta
Line color black
transparency opaque
shine Metallic luster

Tazieffit is a very rarely occurring mineral from the mineral class of "sulfides and sulfosalts" with the chemical composition Pb 20 Cd 2 (As, Bi) 22 S 50 Cl 10 and thus consists of lead , cadmium , arsenic and bismuth, which are variable due to mutual substitution Proportions as well as sulfur and chlorine . Structurally, tazieffit belongs to the sulfosalts .

Tazieffit crystallizes in the monoclinic crystal system , but has so far only been found in the form of fibrous aggregates consisting of tiny crystals with a needle-like habit , a length of up to 400  μm and a width of up to 10 μm. The opaque crystals show a metallic sheen on the surface and are of a silver-gray color that occasionally takes on a magenta tinge. The line color , however, is black.

Etymology and history

Haroun Tazieff, 1972

Was first discovered Tazieffit at a high temperature fumarole on volcano Mutnovsky (English: Mutnovsky ) in the southern part of the Russian peninsula of Kamchatka in the Far Eastern Federal District . The mineral was scientifically described by Michael Zelenski, Anna Garavelli, Daniela Pinto, Filippo Vurro, Yves Moëlo, Luca Bindi, Emil Makovicky and Elena Bonaccorsi, who named it after the well-known French volcanologist Haroun Tazieff (1914-1998).

Type material of the mineral is in the mineralogical collection of the CL Garavelli Museum of the University of Bari under the catalog number 7 / nm (V28), in the Fersman Museum in Moscow under the catalog no. 92674 and at Mines ParisTech ( Ecole des Mines ) in Paris under catalog no. 78986 kept.

classification

Since Mutnovskit was only recognized by the International Mineralogical Association (IMA) as an independent mineral in 2008 , it is not listed in the 8th edition of the Strunz mineral classification, which has been outdated since 1977 . Only in the "Lapis mineral directory", which is still based on this old form of Karl Hugo Strunz's systematic out of consideration for private collectors and institutional collections , the mineral received the system and mineral number. II / E.27-15 . In the "Lapis system" this corresponds to the class of "sulfides and sulfosalts" and there the department "sulfosalts", where Tazieffit, together with Kirkiit , Mutnovskit and Vurroit, forms an independent but unnamed group (as of 2018).

The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and was updated by the International Mineralogical Association (IMA) until 2009, classifies the Tazieffit in the department of “sulfosalts with PbS as a model”. This is further subdivided according to the structural relationship of the corresponding lead minerals, so that the tazieffit (here still under its IMA entry no. IMA 2008-012) can be found in the sub-section "Galena derivatives with lead (Pb)" according to its structure , where it is initially available under the system no. 2.JB was classified without its own group.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the tazieffit to the class of "sulfides and sulfosalts" and there in the department of "sulfosalts". Here it is together with zinkenite , pillaite and pellouxite in the " zinkenite group " 03.08.01 within the subdivision "sulfosalts with the ratio 1 <z / y <2 and the composition (A + ) i (A 2+ ) j [B y C z ], A = metals, B = semimetals, C = non-metals ”.

Crystal structure

Tazieffit crystallizes monoclinically in the space group C 2 / c (space group no. 15) with the lattice parameters a  = 8.3520 (17)  Å ; b  = 45.5920 (92) Å; c  = 27.2610 (55) Å and β = 98.84 (3) ° as well as 4 formula units per unit cell . Template: room group / 15

Education and Locations

Crystal lawn made of needle-like Tazieffit from Mutnowski, Kamtchatka, Russia (field of view 3 mm)

Tazieffit forms as a resublimation product on volcanic fumaroles at a temperature of around 250 to 350 ° C. As Begleitminerale occur among other Greenockit , galena , Mutnovskit , Kudriavit and cadmium-rich Cannizzarit and anhydrite , cristobalite and pyrite on.

Apart from its type locality , the fumarole located about 13 km southeast of the Mutnovsky crater ( 52 ° 21 ′ 0 ″  N , 158 ° 16 ′ 12 ″  E ), no other sites for Mutnovskite are known so far (as of 2017).

See also

literature

  • Michael Zelenski, Anna Garavelli, Daniela Pinto, Filippo Vurro, Yves Moëlo, Luca Bindi, Emil Makovicky, Elena Bonaccorsi: Tazieffite, Pb 20 Cd 2 (As, Bi) 22 S 50 Cl 10 , a new chloro-sulfosalt from Mutnovsky volcano, Kamchatka Peninsula, Russian Federation . In: American Mineralogist . tape 94 , 2009, p. 1312–1324 ( rruff.info [PDF; 1.1 MB ; accessed on November 27, 2017]).
  • Peter A. Williams, Frédéric Hatert, Marco Pasero: New minerals approved in 2008 . In: International Mineralogical Association . 2008, p. 1–13 (English, rruff.info [PDF; 147 kB ; accessed on May 1, 2020] IMA No. 2008-012).

Web links

Commons : Tazieffite  - collection of images, 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: March 2020. (PDF; 2.44 MB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, March 2020, accessed May 1, 2020 .
  2. ↑ a b 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. ↑ David Barthelmy: Tazieffite MineralData. In: webmineral.com. Retrieved May 1, 2020 .
  4. ↑ a b c d e Michael Zelenski, Anna Garavelli, Daniela Pinto, Filippo Vurro, Yves Moëlo, Luca Bindi, Emil Makovicky, Elena Bonaccorsi: Tazieffite, Pb 20 Cd 2 (As, Bi) 22 S 50 Cl 10 , a new chloro -sulfosalt from Mutnovsky volcano, Kamchatka Peninsula, Russian Federation . In: American Mineralogist . tape 94 , 2009, p. 1312–1324 ( rruff.info [PDF; 1.4 MB ; accessed on May 1, 2020]).
  5. ↑ Tazieffite. In: mindat.org. Hudson Institute of Mineralogy, accessed May 1, 2020 .
  6. ↑ 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 May 1, 2020 .
  7. ↑ Find location list for Tazieffit in the Mineralienatlas and Mindat , accessed on May 1, 2020.