Nekrasovite

• IMA 1983-051

Nekrasovit is a very rarely occurring mineral from the mineral class of sulfides and sulfosalts. It crystallizes in a cubic crystal system having a chemical composition Cu26V2 (Sn, As, Sb) and forms 6S32 up to 1 micron wide roundish grains of a red-brown color.

Etymology and history

The mineral was first in 1984 by V.A. Kolavalenker, T. L. Evstigneeva, V.S. Malov, N.V. Trubkin, A. I. Gorshkov and V.R. Geinke found in the Khayragatsch - gold deposit in Chatkal - Kuramin Mountains (eastern Uzbekistan). They named it after the Russian mineralogist Ivan Yakovlevich Nekrasov.

Classification

In the classification by Strunz Nekrasovit is counted among the metal sulfides with a ratio of metal to sulfur, selenium or tellurium of 1:1. After the 8th edition forms a group together with Colusite, germanite, Maikainit, Morozeviczit, Germanocolusit, Ovamboit, Polkovicit, Renierite, Stibiocolusit, Sulvanit and Vinciennit. In the 9th edition it forms with Colusite, germanite, Maikainit, Germanocolusit, Ovamboit and Stibiocolusit a subset of the sulphides of zinc, iron, copper or silver.

In the classification by Dana it forms with Colusite, Germanocolusit and Stibiocolusit the Colusitgruppe, a subgroup of the sulfosalts with the composition ( A ) i ( A2 ) j [By Cz ] (A: Metals, B: semimetals, C. non-metals ) and the ratio of z / y > 4

Education and Locations

Nekrasovit forms in ores in andesite and dacite. It is associated with tetrahedrite, tennantite, Luzonit, Famatinit, pyrite, Mawsonit, chalcopyrite, Emplectit, Laitakarit, bismuth, calcite, quartz and barite.

From the very rare mineral only seven localities (as of July 2010) are known. In addition to the type locality was found Nekrasovit in Massa in Italy, Shiribeshi and Shimoda in Japan, as well as in Bisbee in the U.S. state of Arizona.

Crystal structure

Nekrasovit crystallizes in the cubic crystal system in the space group with the lattice parameters a = 10.73 Å, and one formula unit per unit cell.