Aktashit

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Aktashit
Aktashite-509294.jpg
Aktashite (gray tinge) on mint green, fibrous emmonsite from Moctezuma , Municipio Moctezuma, Sonora, Mexico ( overall size : 2.2 cm × 2.2 cm × 0.9 cm)
General and classification
other names

Actasite

chemical formula Cu 6 Hg 3 [AsS 3 ] 4
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.GA.30 ( 8th edition : II / C.12)
04/03/13/02
Crystallographic Data
Crystal system trigonal
Crystal class ; symbol trigonal-pyramidal; 3
Space group R 3 (No. 146)Template: room group / 146
Lattice parameters a  = 13.73  Å ; c  = 9.33 Å
Formula units Z  = 3
Physical Properties
Mohs hardness ≈ 3.5 ( VHN 50 = 300–346; average 313)
Density (g / cm 3 ) measured: 5.5; calculated: 5.72
Cleavage is missing
Break ; Tenacity uneven to shell-like; brittle
colour grey black
Line color black
transparency opaque
shine Metallic luster
Other properties
Chemical behavior sensitive to nitric acid

Aktashite is a seldom occurring mineral from the mineral class of "sulfides and sulfosalts" with the chemical composition Cu 6 Hg 3 [AsS 3 ] 4 and thus, chemically speaking, a copper - mercury - sulfoarsenide .

With the sulfoantimonide Gruzdevit (Cu 6 Hg 3 [SbS 3 ] 4 ) Aktashite forms a mixed crystal row .

Aktashite crystallizes in the trigonal crystal system , but rarely develops well-formed, pyramidal crystals up to 0.2 mm in size, which can be fused with Gruzdevite in the zone. It is mostly found in the form of xenomorphic grains and granular mineral aggregates .

Etymology and history

Aktashit was first discovered in the antimony- mercury deposit Aktashskoye in the Russian Autonomous Republic of Altai (southwestern Siberia) and described in 1968 by Vladimir I. Vasil'ev, who named the mineral after its type locality . Vasil'ev published his research results on the newly discovered mineral initially without examination by the IMA / CNMNC . However, it was recognized retrospectively in 2008 by the sulfosalts subcommittee.

Type material of the mineral is in the Geological Museum in Novosibirsk (Russia) under the inventory no. III-14/1 and in the Mines ParisTech ( École des mines ) in Paris (France).

classification

In the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the actashite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "sulfides with the molar ratio of metal: S, Se, Te ≈ 1: 1", where he formed the unnamed group II / C.12 together with Gruzdevit , Nowackiit , Sinnerit and Watanabeit .

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), classifies actashite in the category of "sulfoarsenides, sulfoantimonides and sulfobismuthides". This is further subdivided according to the crystal structure and the possible presence of additional sulfur, so that the mineral according to its composition can be found in the subsection "Island sulfarsenides (Neso sulfarsenides) etc., without additional sulfur (S)", where it can be found only together with Gruzdevit and Nowackiit the "Nowackiit group" with the system no. 2.GA.30 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Aktashite to the class of "sulfides and sulfosalts" and there in the department of "sulfosalts". Here it is in the unnamed group 04/03/13 within the subsection “ Sulphosalts with the ratio 3> z / y and the composition (A + ) i (A 2+ ) j [B y C z ], A = metals, B = Semimetals, C = non-metals ”.

Crystal structure

Aktashit crystallizes trigonal in the space group R 3 (space group no. 146) with the lattice parameters a  = 13.73  Å and c  = 9.33 Å as well as 3 formula units per unit cell . Template: room group / 146

The crystal structure of Aktashit consists of a framework of corner-sharing HgS 4 - and CuS 4 - tetrahedra with channels parallel to the Z-axis.

properties

Aktashit is insensitive to standard caustic agents. However, it initially reacts to nitric acid (HNO 3 ) by turning brown and then forming a blue to purple-colored solution.

Aktashit is a good conductor of electricity .

Education and Locations

Aktashit is formed by hydrothermal processes in complex polymetallic deposits containing arsenic and mercury . A large number of accompanying minerals naturally occur in such deposits , including the arsenic and mercury minerals auripigment , cinnabar , enargite , luzonite , realgar and tennantite ; the antimony minerals chalcostibite , stibnite and mercury-containing tetrahedrite, as well as the minerals chalcopyrite , pyrite and sphalerite known as "passages" . In addition, there are rock-forming minerals such as calcite and quartz . Occasionally Dickit can also be found.

As a rare mineral formation, Aktashite could only be detected in a few localities, whereby so far (as of 2016) around 20 localities are known. In addition to its type locality Aktashskoye in south-western Siberia, the mineral was also found in Russia in the arsenic-mercury-antimony deposit Gal-Khaya in Sakha ( Yakutia ) in eastern Siberia, in the Vorontsovskoe gold deposit near Turinsk in the Sverdlovsk Oblast in the Urals and in the Saranovskii mine near Gornozavodsk in the Perm region.

In Europe, Aktashite was found in the hydrothermal, stratiform deposit of Jas Roux in the commune of Valgaudemar (Hautes-Alpes) in France and in the Miniera di Monte Arsiccio near Sant'Anna di Stazzema in the Italian region of Tuscany.

Other locations include Bomby in the Thunder Bay District (Ontario) in Canada, in the Lianhecun ore deposit in Jiuzhaigou district in the Chinese province of Sichuan, in the arsenic deposit Lukhumi near Mestia (Ratscha-Letschchumi and Lower Wanetia ) in Georgia, the mine Zareh Shuran near Takab in West Azerbaijan , the antimony-mercury deposits in the Ferghana Valley and in the Alai Mountains in Kyrgyzstan, the Moctezuma gold mine at the same name in the Mexican state of Sonora and in the ore mines near Lynn in Eureka County and Adam Peak in Humboldt County in the US - State of Nevada.

See also

literature

  • VI Vasil'ev: New ore minerals of the mercury deposits of Gornyi Altai and their parageneses . In: Voprosy metallogenii rtuti (Problems of mercury metallogeny) . Izdatelstvo "Nauka", Moscow 1968, p. 111-129 .
  • Michael Fleischer : New mineral names . In: American Mineralogist . tape 56 , 1971, p. 358–362 (English, minsocam.org [PDF; 335 kB ; accessed on December 26, 2018]).
  • Vladimir I. Vasil'ev, Natalie V. Pervukhina, Stanislav V. Borisov, Svetlana A. Magarill, DY Naumov, NV Kurat'eva: Aktashite Cu 6 Hg 3 As 4 S 12 from the Aktash deposit, Altai, Russia: Refinement and crystal chemical analysis of the structure . In: Geology of Ore Deposits . tape 52 , 2010, p. 656-661 , doi : 10.1134 / S1075701510070184 (English).

Web links

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

Individual evidence

  1. ↑ Hans Jürgen Rösler : Textbook of Mineralogy . 4th, revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p.  349 .
  2. ↑ a b c d e f 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.  120 (English).
  3. ↑ David Barthelmy: Aktashite Mineral Data. In: webmineral.com. Accessed December 26, 2018 .
  4. ↑ a b c d e Aktashite . 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; 61  kB ; accessed on December 26, 2018]).
  5. ↑ 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 .
  6. ↑ Aktashite. In: mindat.org. Hudson Institute of Mineralogy, accessed December 26, 2018 .
  7. ↑ Vladimir I. Vasil'ev, Natalie V. Pervukhina, Stanislav V. Borisov, Svetlana A. Magarill, DY Naumov, NV Kurat'eva: Aktashite Cu 6 Hg 3 As 4 S 12 from the Aktash deposit, Altai, Russia: Refinement and crystal chemical analysis of the structure . In: Geology of Ore Deposits . tape 52 , 2010, p. 656-661 , doi : 10.1134 / S1075701510070184 (English).
  8. ^ A b Michael Fleischer : New mineral names . In: American Mineralogist . tape  56 , 1971, p. 358–362 (English, minsocam.org [PDF; 335 kB ; accessed on December 26, 2018] p. 2).
  9. ↑ Find location list for Aktashite in the Mineralienatlas and Mindat