Wodginite
Wodginit is a rarely occurring mineral from the mineral class of " oxides and hydroxides ". It crystallizes in the monoclinic crystal system with the chemical composition MnSnTa2O8 and is therefore a manganese -tin -tantalum oxide.
Wodginit developed flattened dipyramidal or prismatic crystals which can be up to 15 centimeters long and are usually disposed in radially disposed groups. But it also occurs in the form of granular to moderate ( coarse ) aggregates. The mineral is generally opaque and transparent in thin layers. Its color varies from reddish brown, dark brown and black and its stroke color between brown and light brown. The crystal surfaces have a faint metallic luster.
Etymology and history
Was first discovered in the Wodginit Wodgina mine in Western Australia's Pilbara region 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In the now outdated but still in use 8th edition of the mineral classification by Strunz the Wodginit belonged to the department of " oxides with molar ratio of metal: oxygen = 1: 2 ( MO2 and related compounds ) ," where he, along with Ferrotitanowodginit, Ferrowodginit, Ixiolit Koragoit, Lithiowodginit, Qitianlingit and Titanowodginit the unnamed group IV/D.17 formed.
The 9th edition valid since 2001 and of the International Mineralogical Association (IMA ) used the Strunz'schen Mineral classification assigns the Wodginit also in the department of " Metal: Oxygen = 1: 2 and comparable " one. However, this is further divided according to the relative size of the involved cations and the crystal structure, so that the mineral according to its composition and its construction in the subdivision: is to find "With medium-sized cations chains of edge-sharing octahedra ", where it as a name, the " Wodginitgruppe " with the system number. Forms 4.DB.40 and the other members Ferrotitanowodginit, Ferrowodginit, Lithiotantit, Lithiowodginit and Titanowodginit.
The mainly common in English-speaking classification of minerals according to Dana assigns the Wodginit in the class of " oxides and hydroxides " and then in the Department of a " multiple oxides with Nb, Ta and Ti ". Here he is in the Wodginitgruppe with the system no. 08:01:08 to find within the subdivision " Multiple Oxides with Nb, Ta and Ti with the formula ABO4 ".
Education and Locations
Typically in zoned pegmatites in amphibolite occurs Wodginit on together with tantalite, albite, quartz, muscovite, Tapiolite, Mikrolith and microcline.
A rare mineral formation Wodginit could be detected only in a few localities, where so far (as of 2013) are about 60 localities known as. Apart from its type locality Wodgina mine in the Pilbara region, the mineral only appeared in "Green Bushes Tinfield " ( Zinnfeld ) in the administrative area Bridgetown - Greenbushes Shire in Australia.
Other known localities include
- Western Europe: the Viitaniemi pegmatites in the area around Eräjärvi - Orivesi in Finland, Varuträsk ( Västerbotten ) in Sweden, Krasno nad Teplou ( German Schoenfeld ) in Czech Republic
- Eastern Europe and Central Asia: the tantalum deposits Ognevka and Yubileinoye in eastern Kazakhstan, Vasin - Myl'k on the Russian Kola Peninsula
- East Asia: the " Paprok Mine" in the Afghan district Kamdesh, the Nanping pegmatite field ( Fujian) and the " Yichun Mine" (Jiangxi ) in China, Tawara ( Tahara ) in Gifu Prefecture on the Japanese island of Honshu, the Unchzhul - solid in Mongolia, which is part of the Mongolia and southern Siberia Sayan Mountains
- Africa: the tantalum -tin deposit near Marsa Alam in Egypt and around Desi, the " Kenticha Mine" in the Ethiopian province of Sidamo - Borana, Damaraland in Namibia
- North America: several places in the Canadian provinces of Manitoba, Northwest Territories and Ontario, several places in different States of the USA
- South America: the pegmatites of San Elías and La Viquita in the Argentine Department of Chacabuco (San Luis ), several places in the Brazilian states of Minas Gerais and Paraíba
Crystal structure
Wodginit crystallizes in the monoclinic space group C2 / c ( Raumgruppen-Nr. 15) with the lattice parameters a = 9.50 Å; b = 11.46 Å; c = 5.14 Å and 90.5 ° β = 7 and formula units per unit cell.