Stilleite

Stilleit, chemically zinc selenide is a very rarely occurring mineral from the mineral class of sulfides and sulfosalts. It crystallizes in the cubic crystal system with the chemical composition of ZnSe and forms microscopic inclusions in linnaeite of gray color.

Etymology and history

Stilleit was first found in 1956 by Paul Ramdohr in the Shinkolobwe mine at Shinkolobwe in the Katanga province of the Democratic Republic of Congo. He named it after the German geologist Hans silence.

Classification

In the classification by Strunz Stilleit is counted among the metal sulfides with a ratio of metal to sulfur, selenium or tellurium of 1:1. After the 8th edition forms the Sphaleritgruppe together with Coloradoite, Hawleyit, Rudashevskyit, Polhemusit, sphalerite, and Metacinnabarit Tiemannit. The 9th edition, it is with these minerals and Sakuraiit a subset of sulfides of zinc, iron, copper or silver.

In the classification by Dana it forms with Coloradoite, Hawleyit, Rudashevskyit, sphalerite, and Metacinnabarit Tiemannit the sphalerite - subgroup of sulfides, selenides and tellurides with the composition AmBn Xp, with (m n): p = 1:1.

Education and Locations

Stilleit forms along with other selenides or as an inclusion in linnaeite. It is depending on the locality associated with pyrite, linnaeite, Clausthalite, selenium Vaesit, molybdenite and dolomite or Tiemannit, Clausthalite, Eukairit, Umangit and Klockmannit.

There are only a few known localities of the mineral. In addition to the type locality in Katanga was Stilleit still at St. Andrew Berg and Abberode in the Harz ( Germany ) and found in several localities in the Argentine province of La Rioja.

Crystal structure

Stilleit crystallizes in the cubic crystal system in the space group with the lattice parameters a = 5.667 Å and four formula units per unit cell.