Laurite

Laurit is a rarely occurring mineral from the mineral class of sulfides and sulfosalts. It crystallizes in a cubic crystal system having a chemical composition RUS2 and forms up to one millimeter wide, octahedral, cubic, or disdodekaedrische crystals of black color. Also rounded grains and inclusions in other minerals are known.

Etymology and history

The mineral was found in 1866 by Waitz in Tanah According to the, now part of Indonesia part of Borneo. It was chemically analyzed by Friedrich Wöhler and crystallographically by Wolfgang Sartorius von Walter Hausen in Göttingen. Its name comes from the mineral Wöhler after the wife of a fellow chemist.

Classification

In the classification by Strunz Laurit is counted among the sulfides and sulfosalts. After the 8th edition forms together with Aurostibit, Cattierit, Changchengit, Dzharkenit, Erlichmanit, Fukuchilit, Geversit, Hauerite, Insizwait, Krut'ait, Maslovit, Mayingit, Michenerit, Padmait, Penroseite, pyrite, Sperrylite, Testibiopalladit, Trogtalit, Vaesit and Villamaninit pyrite group, a sub-group of the sulfides with a ratio of metal to sulfur, selenium or tellurium, of < 1:1. In the 9th edition it forms with Aurostibit, Bambollait, beta iridisit, Cattierit, Dzharkenit, Erlichmanit, Fukuchilit, Gaotaiit, Geversit, Hauerite, Insizwait, Krutaite, Penroseite, pyrite, Sperrylite, Trogtalit, Vaesit and Villamanínit a subset of the sulfides with a ratio of sulfur to metal of 1:2, and iron, cobalt, nickel or platinum group elements (PGE ).

In the classification by Dana, it belongs to the pyrite group, a subgroup of the sulfides, selenides and tellurides with the composition AmBn Xp, with (m n): p = 1:2.

Modifications and varieties

Laurit forms with Erlichmannit a solid solution series can be exchanged at the ruthenium to osmium.

Education and Locations

Laurit forms in ultramafic complexes. It is associated with cooperite, Braggit, Sperrylite, other platinum metal minerals and chromite.

There are a total of 119 known localities (April 2010 ) of Laurits. In addition to the type locality was found the mineral, among others in the Bushveld complex in South Africa, the Stillwater Complex, Yuba River and other places in the United States, British Columbia (Canada), Sierra Leone, the Aldanhochland in Russia, Swenyhorodka in Ukraine and the Howard River in New Zealand.

Crystal structure

Laurit crystallizes in the cubic crystal system in the space group with the lattice parameters a = 5.6135 Å and four formula units per unit cell.