Bismite

UntilWed (deprecated bismuth ocher ) is a mineral from the mineral class of oxides and hydroxides. It crystallizes in the monoclinic crystal system with the chemical composition Bi2O3 and usually develops granular to massive mineral aggregates or earthy and powdery coatings in yellow, yellow-green or gray-green color. Crystals occur only rarely, and then only microscopic.

It is very soft and easy to grind, opaque, and from yellow to gray to green shimmer or matte. It consists of bismuth oxide Bi2O3 89.7 % bismuth and is contaminated with iron, copper and arsenic.

Etymology and history

Was first described in 1753 by Johan Gottschalk untilWed Wallerius, who named the mineral after its composition. As a type locality to Wolfgang dimensions pit field ( Pucherschacht ) at Neustädtel in the Erzgebirge.

Classification

In the old ( 8th edition ) and new classification of minerals according to Strunz ( 9th edition ) is one of the untilWed to the Department of " oxides with the molar ratio of metal: oxygen = 2: 3 ," said department in the new Strunz'schen Mineral classification 5 was expanded and also precise and comparable divided by the size of the cations: still the oxides with the molar ratio of metal: oxygen = 3. Accordingly, the mineral is now in the subsection "With medium-sized cations ", where it forms together with sillenite and Sphaerobismoite own group.

The classification of minerals according to Dana assigns the untilWed also in the class of oxides, but there in the department of "simple oxides with a cation charge of 3 , and the general formula A2O3 ", where it forms a group together with Claudetit.

Modifications and varieties

The connection Bi2O3 occurs in nature on dimorphic and can in addition also untilWed in the tetragonal structure of the Sphaerobismoits (space group P 42212 or P 41 / n) crystallize.

Education and Locations

UntilWed formed by oxidation of bismuth and is therefore usually as a coating, tough and disseminated in pseudomorphs after Bismuthinite and aikinite.

So far, 156 localities were registered (as of 2009), so among other things, some regions in Australia; Departamento La Paz and Potosí Department in Bolivia; on the Rio Grande in Brazil; Guizhou, Qinghai and Yunnan in China; Baden- Württemberg ( Black Forest), Bavaria (Bavarian and Upper Palatinate Forest ), Hesse (Odenwald ), North Rhine -Westphalia and Rhineland -Palatinate (winner country), Saxony -Anhalt (Harz ), Saxony (Erzgebirge) and Thuringia ( Vogtland) in Germany; Alsace, Auvergne, and Brittany in France; Attica in Greece; England in the United Kingdom; Lombardy, Piedmont and Sardinia in Italy; Honshu and the Nansei Islands in Japan; Ontario, Canada; Kazakhstan; Kivu in the Democratic Republic of Congo; Antananarivo and Fianarantsoa in Madagascar; Durango in Mexico; Erongo and Kunene in Namibia; Aust- Agder in Norway; Carinthia and Styria in Austria; Lower Silesia in Poland; Russia (northern and western Siberian regions); Västmanland in Sweden; Canton of Valais in Switzerland; Banská Bystrica and Košice in Slovakia; Bohemia in the Czech Republic; and many regions in the United States.

Crystal structure

UntilWed crystallizes in the monoclinic crystal system, space group P 21 / c with lattice parameters a = 5.8486 Å; b = 8.1661 Å, c = 7.5097 Å and β = 113.00 °, and four formula units per unit cell.