Tusionite

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Tusionite
Tusionite.jpg
Yellow tusionite crystal aggregate from Řečice , Vysočina region, Czech Republic
General and classification
other names

IMA 1982-090

chemical formula Mn 2+ Sn 4+ [BO 3 ] 2
Mineral class
(and possibly department) 		Borates
System no. to Strunz
and to Dana 		6.AA.15
03/24/03/02
Crystallographic Data
Crystal system trigonal
Crystal class ; symbol trigonal-rhombohedral; 3
Space group R 3 (No. 148)Template: room group / 148
Lattice parameters a  = 4.781  Å ; c  = 15.381 Å
Formula units Z  = 3
Physical Properties
Mohs hardness 4.5 to 5 ( VHN 40 = 400–500 {0001}, 700–750 ⊥ {0001})
Density (g / cm 3 ) measured: 4.73; calculated: 4.85
Cleavage completely after {0001}
colour colorless, honey to brownish yellow
Line color White
transparency transparent to translucent
shine Glass gloss
Crystal optics
Refractive indices n ω  = 1.854
n ε  = 1.752 (2)
Birefringence δ = 0.102
Optical character uniaxial negative

Tusionite is a very seldom occurring mineral from the mineral class of " borates " with the chemical composition Mn 2+ Sn 4+ [BO 3 ] 2 and therefore, chemically speaking, a manganese - tin borate.

Tusionite crystallizes in a trigonal crystal system and develops thin tabular crystals up to about 1.5 cm in size with a glass-like sheen on the surfaces, which usually come together to form rosette-shaped mineral aggregates . It is also often found in the form of inclusions in other minerals such as phenakite and petalite .

In its pure form, Tusionite is colorless and transparent. However, due to multiple refraction due to lattice construction defects or polycrystalline formation, it can also appear white and, due to foreign admixtures, take on a honey- to brownish-yellow color, with the transparency decreasing accordingly.

Etymology and history

Tusionite was first discovered in 1981 in the Pamir Mountains , more precisely in the southwestern Tusion Valley in the Tajik province of Berg-Badachschan . It was first described in 1983 by SI Konovalenko, AV Voloshin, Ya. A. Pakhomovskiy, SS Anen'yev, GA Perlina, DL Rogachev and VY Kuznetsov, who named the mineral after its type locality .

Type material of the mineral is in the Mineralogical Museum of the State University under the catalog no. 17096 and in the State Mining University in Saint Petersburg under catalog no. 1661/1 and in the Fersman Museum of the Russian Academy of Sciences in Moscow under catalog no. 82546 kept.

classification

Since the tusionite was only discovered in 1982 and recognized as a separate mineral, it is not listed in the outdated 8th edition of the mineral classification according to Strunz . Only in the “Lapis Mineral Directory”, which was last updated in 2018, which is still based on the classic system of Karl Hugo Strunz out of consideration for private collectors and institutional collections , the mineral received the system no. V / G.02-20 . In the "Lapis system" this corresponds to the class of "nitrates, carbonates and borates" and there the department "Inselborate" (with [BO 3 ] 3 -Islands), where Tusionite together with Nordenskiöldin forms an independent but unnamed group .

The 9th edition of Strunz's mineral systematics, valid since 2001 and updated by the International Mineralogical Association (IMA) until 2009, assigns tusionite to the newly defined class of "borates" and there in the department of "monoborates". This is further subdivided according to the possible presence of additional anions and the crystal structure, so that the mineral according to its composition and structure in the sub-section “BO 3 without additional anions; 1 (Δ) ”can be found where, together with Nordenskiöldin, the“ Nordenskiöldin group ”with the system no. 6.AA.15 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the tusionite like the lapis systematics to the common class of "carbonates, nitrates and borates" and there to the department of "anhydrous borates". Here he can also be found together with Nordenskiöldin in the unnamed group 03/24/03 within the sub-section “Anhydrous borates with (A) m (B) n [XO 3 ] p ”.

Chemism

In the idealized composition Mn 2+ Sn 4+ [BO 3 ] 2 , tusionite consists of 18.86% manganese (Mn), 40.76% tin (Sn), 7.42% boron (B) and 32.96% oxygen (O). When analyzing natural tusionites from their type locality in Tajikistan, however, small amounts of iron and calcium were also found , which can partially replace the manganese .

Crystal structure

Tusionite crystallizes trigonal in the space group R 3 (space group no. 148) with the lattice parameters a  = 4.781  Å and c  = 15.381 Å as well as three formula units per unit cell . Template: room group / 148

Education and Locations

Tusionite forms hydrothermally in the late phase of mineral precipitations and is typically found in miarolitic cavities of granitic pegmatites .

At its type locality in Tajikistan , tusionite was found in the rock samples from the upper course of the Tusion river, associated with albite , danburite , hambergite , orthoclase , quartz , tetrawickmanite and tourmaline .

So far (as of 2019) only two other sites are known worldwide. In particular, these are the municipality of Řečice in the Czech Kraj Vysočina and the phenakite mine near Khetchel in the Kyaukme district in the Shan state of Myanmar.

See also

literature

  • SI Konovalenko, AV Voloshin, Ya. A. Pakhomovskiy, SS Anen'yev, GA Perlina, DL Rogachev, VY Kuznetsov: Тусионит MnSn (BO 3 ) 2 - новый борат из гранитных пегманититов пегматитов Юга . In: Doklady Akademii Nauk SSSR . tape 272 , no. 6 , 1983, pp. 1449–1453 (Russian, transliteration: Tusionite, MnSn (BO 3 ) 2 - novyy borat iz granitnykh pegmatitov yugo-zapadnogo Pamir ).
  • SI Konovalenko, AV Voloshin, YA Pakhomovskiy, SS Anen'yev, GA Perlina, DL Rogachev, VY Kuznetsov: Tusionite, MnSn (BO 3 ) 2 , a new borate from granite pegmatite of southwestern Pamir . In: International Geology Review . tape 26 , no. 4 , 1984, pp. 481-485 , doi : 10.1080 / 00206818409466576 (English).
  • Pete J. Dunn, Louis J. Cabri, James A. Ferraiolo, Joel D. Grice, John L. Jambor, Wolfgang Mueller, James E Shigley, Jacek Puziewicz, David A. Vanko: New Mineral Names . In: American Mineralogist . 69 date = 1984, p. 1193 (English, minsocam.org [PDF; 853 kB ; accessed on October 3, 2019]).

Web links

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

Individual evidence

  1. ^ 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.  329 (English).
  2. ↑ a b c d Mark Cooper, Frank C. Hawthorne, Milan Novák: The crystal structure of tusionite, MnSn (BO 3 ) 2 , a dolomite-structure borate . In: The Canadian Mineralogist . tape 32 , 1994, pp. 903–907 (English, rruff.info [PDF; 403 kB ; accessed on October 3, 2019]).
  3. ^ A b David Barthelmy: Tusionite Mineral Data. In: webmineral.com. Retrieved October 3, 2019 .
  4. ↑ 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 .
  5. ↑ a b c d e Tusionite . 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 October 3, 2019]).
  6. ↑ a b c Tusionite. In: mindat.org. Hudson Institute of Mineralogy, accessed October 3, 2019 .
  7. ↑ Tusionite - Photo Gallery. In: mindat.org. Hudson Institute of Mineralogy, accessed October 3, 2019 (with images of tusonite inclusions in phenakite and petalite).
  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 October 3, 2019 .
  9. ↑ Find location list for Tusionite at the Mineralienatlas and at Mindat , accessed on October 3, 2019.