Lenait

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Lenait
Lenaite - inclusion in test sample for SEM - Privolnoye, Sakha Republic (Yakutia), Russia.jpg
Lenaite as an inclusion in a test sample for an SEM image - Privolnoye, Sacha (Yakutia)
General and classification
other names

IMA 1994-008

chemical formula AgFeS 2
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.CB.10a
02.09.01.05
Crystallographic Data
Crystal system tetragonal
Crystal class ; symbol ditetragonal-pyramidal; 4 mm
Space group P 4 2 mc (No. 105)Template: room group / 105
Lattice parameters a  = 5.64  Å ; c  = 10.34 Å
Formula units Z  = 4
Physical Properties
Mohs hardness 4 to 4.5
( VHN 10 = 270–360, average 310)
Density (g / cm 3 ) calculated: 4.63
Cleavage not defined
colour steel gray to black
Line color dark gray to black
transparency opaque
shine Metallic luster

Lenaite is a very seldom occurring mineral from the mineral class of " sulfides and sulfosalts " with the chemical composition AgFeS 2 and therefore, chemically speaking, a silver - iron sulfide.

Lenaite crystallizes in the tetragonal crystal system and has so far only been found in the form of steel-gray to black, metallically shiny , isometric crystal grains up to about 0.2 mm in size.

Etymology and history

Was first discovered Lenait in the silver - antimony - mercury - deposit Khachakchan in Verkhoyansk Mountain in the members of the Russia Republic Sacha (Jakutien). It was first described in 1995 by VA Amuzinskii, Yu. Ya. Zhdanov, NV Zayakina and NV Leskova, who named the mineral after the Lena river that ran near the site .

The type material of the mineral is stored in the Geological Museum of the Yakutsk Science Center of the Russian Academy of Sciences .

classification

Since the Lenaite was only discovered in 1995 and recognized as an independent mineral, it is not listed in the 8th edition of the mineral classification according to Strunz, which was last updated in 1982 . Only in the "Lapis mineral directory", which is based on the classic system of Karl Hugo Strunz out of consideration for private collectors and institutional collections , the mineral received the system and mineral number. II / C.03-25 and thus belongs to the “chalcopyrite group” in the classical system within the section “Sulphides with metal: S, Se, Te ≈ 1: 1”.

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), also classifies Lenait in the category of "Metal sulfides, M: S = 1: 1 (and similar)". However, this is further subdivided according to the metals involved in the connection, so that the mineral can be found in the sub-section "with zinc (Zn), iron (Fe), copper (Cu), silver (Ag) etc." according to its composition where, together with chalcopyrite, eskebornite, gallite, laforêtite and roquesite, the “chalcopyrite group” with the system no. 2.CB.10a forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Lenaite to the class of "sulfides and sulfosalts" and there in the department of "sulfide minerals". Here it is also together with chalcopyrite, eskebornite, gallite, roquesite and laforêtite in the "chalcopyrite group (tetragonal: I 4 2 d )" with the system no. 02.09.01 within the sub-section " Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 1: 1 ".

Crystal structure

Lenaite crystallizes tetragonally in the space group P 4 2 mc (space group no. 105) with the lattice parameters a  = 5.64  Å and c  = 10.34 Å as well as 4 formula units per unit cell . Template: room group / 105

Education and Locations

Lenaite is found in goethite - pseudomorphoses after magnesium-containing siderite and in quartz siderite veins. Accompanying minerals are therefore mainly goethite, but also acanthite , Ag – Hg amalgam , chalcopyrite , galena , stephanite and tetrahedrite .

As a very rare mineral formation, Lenaite could only be detected in a few samples, with fewer than 10 locations being documented worldwide (as of 2018). In addition to its type locality in the Khachakchan silver-antimony-mercury deposit , the mineral was also found in Russia in the nearby, similar deposit of Nochnoe and in the Privolnoye mine in the Sakha Republic, near Rodnikovoe on the Kamchatka Peninsula , in the Gulinskii massif the Maimecha and Kotui rivers in the Krasnoyarsk region and in the Teploe gold-silver deposit near Omsukchan in the Kolyma River Valley in the Far East Federal District .

Other secured sites are the Kiziltepe deposit near Sındırgı in the Turkish province of Balıkesir and the epithermal gold-silver-tellurium deposit Geis Mine (also Gies Mine ) in the Warm Springs district ( Fergus County ) in the US state of Montana.

The other sites of the St. Anna mine near Annaberg in Lower Austria, the Yatani mine near Yonezawa in the prefecture of Yamagata on the Japanese island of Honshū and the Tynebottom mine near Garrigill in the Eden district (Cumbria county) and two other deposits in Russia have not yet been verified.

See also

literature

  • VA Amuzinskii, Yu. Ya. Zhdanov, NV Zayakina, NV Leskova: Lenaite, AgFeS 2 , a new mineral species . In: Zapiski Vserossiyskogo Mineralogicheskogo Obshchestva . tape 124 , no. 5 , 1995, p. 85–91 (Russian, minsoc.ru [PDF; 85 kB ; accessed on January 14, 2019] Brief description in English).
  • John L. Jambor, Vladimir A. Kovalenker, Jacek Puziewicz, Andrew C. Roberts: New Mineral Names . In: American Mineralogist . tape 81 , 1996, pp. 1282–1286 (English, minsocam.org [PDF; 482 kB ; accessed on January 14, 2019]).

Web links

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

Individual evidence

  1. ^ IMA / CNMNC List of Mineral Names; November 2018 (PDF 1.7 MB)
  2. ↑ 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.  77 .
  3. ↑ David Barthelmy: Lenaite MineralData. In: webmineral.com. Retrieved January 14, 2019 .
  4. ↑ 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 .
  5. ^ A b John L. Jambor, Vladimir A. Kovalenker, Jacek Puziewicz, Andrew C. Roberts: New Mineral Names . In: American Mineralogist . tape 81 , 1996, pp. 1282–1286 (English, minsocam.org [PDF; 482 kB ; accessed on January 14, 2019]).
  6. ↑ Lenaite. In: mindat.org. Hudson Institute of Mineralogy, accessed January 14, 2019 .
  7. ↑ a b Lenaite . 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 January 14, 2019]).
  8. ↑ Map with position and number of locations for Lenait. In: mindat.org. Hudson Institute of Mineralogy, accessed January 14, 2019 .
  9. ↑ a b List of localities for Lenaite in the Mineralienatlas and Mindat