Wodginite

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Wodginite
Wodginite-den07-27a.jpg
Wodginite crystal from Linópolis , Minas Gerais , Brazil (size: 9.4 × 3.6 × 2.6 cm)
General and classification
chemical formula MnSnTa 2 O 8
Mineral class
(and possibly department) 		Oxides and hydroxides
System no. to Strunz
and to Dana 		04.DB.40 ( 8th edition : IV / D.17)
08.01.08.01
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Room group (no.) C 2 / c (No. 15)
Lattice parameters a  = 9.50  Å ; b  = 11.46 Å; c  = 5.14 Å
β  = 90.5 °
Formula units Z  = 7
Frequent crystal faces {111}
Twinning Often penetration twins after {001} or {100}
Physical Properties
Mohs hardness 5.5 to 6
Density (g / cm 3 ) measured: 7.19 to 7.36; calculated: 7.69 to 7.81
Cleavage no
Break ; Tenacity uneven; brittle
colour reddish brown, dark brown to black
Line color brown to dark brown
transparency opaque, translucent in thin layers
shine weak metallic luster

Wodginite is a rarely occurring mineral from the mineral class of " oxides and hydroxides ". It crystallizes in the monoclinic crystal system with the chemical composition MnSnTa 2 O 8 and is therefore a manganese - tin - tantalum oxide.

Wodginite develops flattened, dipyramidal or prismatic crystals that can be up to 15 centimeters long and are usually arranged in radially arranged groups. But it also occurs in the form of granular to massive (coarse) aggregates . The mineral is generally opaque and only translucent in thin layers. Its color varies between reddish brown, dark brown and black and its line color between brown and light brown. The crystal surfaces have a faint metallic sheen .

Etymology and history

Wodginite was first discovered in the Wodgina Mine in the Western Australian region of Pilbara and described in 1963 by Ernest Henry Nickel , JF Rowland, RC McAdam, who named the mineral after its type locality .

classification

In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the Wodginite belonged to the department of "Oxides with a molar ratio of metal: oxygen = 1: 2 (MO 2 and related compounds)", where it was used together with Ferrotitanowodginit , Ferrowodginit , Ixiolit , Koragoite , lithiowodginite , qitianlingite and titanowodginite formed the unnamed group IV / D.17 .

The 9th edition of Strunz's mineral systematics, which has been in force since 2001 and is used by the International Mineralogical Association (IMA), also classifies Wodginite in the category of "Metal: Oxygen = 1: 2 and comparable". However, this is further subdivided according to the relative size of the cations involved and the crystal structure, so that the mineral is classified in the sub-section “With medium-sized cations; Chains of edge-linked octahedra "can be found, where it is named after the" Wodginite group "with the system no. 4.DB.40 and the other members Ferrotitanowodginit, Ferrowodginit, Lithiotantit , Lithiowodginit and Titanowodginit forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Wodginite to the class of "Oxides and Hydroxides" and there in the section of "Multiple Oxides with Nb, Ta and Ti". Here it is in the Wodginite group with system no. 08.01.08 to be found in the subsection "Multiple oxides with Nb, Ta and Ti with the formula ABO 4 ".

Education and Locations

Epitaxial intergrowth of Wodginite (outside) and Cassiterite (inside) from Lavia Jabuti, Galileia, Minas Gerais , Brazil (size: 3.7 cm × 1.5 cm × 0.7 cm)

Typically, Wodginite occurs in zoned pegmatites in amphibolite together with tantalite , albite , quartz , muscovite , tapiolite , microlite and microcline .

As a rare mineral formation, Wodginite could only be detected at a few sites, whereby so far (as of 2013) around 60 sites are known. In addition to its type locality Wodgina Mine in the Pilbara region, the mineral occurred in Australia only in "Greenbushes Tinfield" ( tin field ) in the administrative region of Bridgetown-Greenbushes Shire .

Other well-known sites are among others

Crystal structure

The figure shows that the columbite group (including tantalite) and wodginite can be understood as superstructures of ixiolite .

Wodginite crystallizes monoclinically in the space group C 2 / c (space group no. 15) with the lattice parameters a  = 9.50  Å ; b  = 11.46 Å; c  = 5.14 Å and β = 90.5 ° and 7 formula units per unit cell .

literature

  • EH Nickel, JF Rowland, RC McAdam: Wodginite - a new tin-manganese tantalate from Wodgina, Australia and Bernic Lake, Manitoba , In: The Canadian Mineralogist , Volume 7 (1963), pp. 390-402

Web links

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

Individual evidence

  1. ↑ a b c d e Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  212 .
  2. ↑ Webmineral - wodginite
  3. ↑ a b c Wodginite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 70.8 kB )
  4. ↑ Mindat - Number of localities for Wodginite
  5. ↑ Find location list for Wodginit in the Mineralienatlas and Mindat
  6. ↑ Ercit, TS, Černý, P., Hawthorne, FC: The wodginite group. III. Classification and new species . In: Canadian Mineralogist . 36, 1992, pp. 633-638.