Clausthalite

Clausthalite (deprecated selenium, lead) is a rarely occurring mineral from the mineral class of sulfides and sulfosalts, more precisely of the sulfides with a ratio of metal to sulfur, selenium or tellurium of 1:1. Together with galena, it forms the Galena Claustalit series.

Clausthalite crystallizes in the cubic crystal system with the chemical formula PbSe in evolution of massive, granular to massive mineral aggregates in lead- gray to bluish color.

Special Features

Clausthalite can be solved with sulfuric and nitric acids. He also developed during heating before the blowpipe a strong, radish like to foul smell, which is typical of selenium and selenium compounds in this method.

Etymology and history

The mineral was found in 1832 by François Sulpice Beudant near Clausthal- Zellerfeld in the Upper Harz and named after its type locality, the village of Clausthal.

Modifications and varieties

The variety Lerbachit (Hg, Pb ) Se, named after the mountain resort type locally Lehrbach, which consists of a mixture of Clausthalite and Tiemannit

Classification

In the classification by Strunz Clausthalite is classified in the sulfides and sulfosalts. It is counted among the sulfides with a ratio of metal to sulfur, selenium or tellurium of 1:1. In the eighth edition, it made with Alabandin, Altait, Crerarit, galena, Keilit, Niningerit and oldhamite a group. In the ninth edition, the sulfides are further subdivided according to cations, there is Clausthalite find with these minerals and Cuboargyrit and Schapbachit in the class of metal sulfides with tin, lead or mercury.

In the classification of minerals according to Dana it forms with Alabandin, Altait, Borovskit, Crerarit, galena, Keilit, Niningerit and oldhamite a subset of the sulfides - including selenides and tellurides - with the composition AmBn Xp, with (m n): p = 1:1.

Education and Locations

Clausthalite formed hydrothermally in low-sulfur deposits. He is associated with other selenides, such as Tiemannit and Klockmannit.

Clausthalite is probably the most common natural selenide.

Locations include Cacheuta in Argentina, Pacajake in Bolivia, the Erzgebirge ( -Alberoda ) in Germany, on Lake Athabasca in Canada, Siberia in Russia, Skrikerum in Sweden, Předbořice, Bukov and Zlatkov in the Czech Republic, and Colorado in the United States.

Crystal structure

Clausthalite crystallizes in the cubic crystal system in the space group and is isotypic with the sodium chloride structure. The lattice parameter a is 6.124 angstroms. The unit cell has slightly longer axes than in the isotypic also galena (PbS, 5,936 angstroms). This is compared to the slightly larger ionic radius of the selenide ion ( Se2 ) in Clausthalite with the sulfide ions (S2 - ) due in Galena. Since sulfur and selenium are often able to replace in crystal structures of each other, the lattice parameter of a solid solution Pb (S, Se), depending on the proportion of the corresponding element, lie between the values ​​mentioned above.

Use

Clausthalite forms with galena a complete solution series. For this reason a few percent selenium in many galena deposits contain. In the lead recovery the selenide present is separated and is used as a source of elemental selenium and other selenium compounds.