Germanite

Germanite is a very rarely occurring mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the cubic crystal system with the composition Cu13Fe2Ge2S16, is so chemically seen a copper iron germanium sulfide.

Germanite is opaque in any form and is found predominantly in the form of massive or granular intergrown with Renierite mineral aggregates with metallic luster on the surfaces. However idiomorphic crystals were observed under the microscope. Its color is usually pink or reddish gray with a distinct purplish hue, which transforms after some time due to starting in to a deep violet.

Special Features

Germanite is difficult to melt and decomposes when heated. In nitric acid it is soluble.

Etymology and history

The mineral was first discovered in 1920 by G. Schneiderhöhn in the type locality Tsumeb in Namibia and described, but not investigated in detail. 1921 W. Klein found again in Tsumeb to him unknown mineral and sent it to the Berlin mineralogist O. Pufahl who examined it more closely and determined the composition. This named the new mineral finally in 1922 the contained element germanium germanite.

Classification

In the classification by Strunz germanite 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, Germanocolusit, Maikainit, Morozeviczit, Nekrasovit, Ovamboit, Polkovicit, Renierite, Stibiocolusit, Sulvanit and Vinciennit. In the 9th edition it forms with Colusite, Germanocolusit, Maikainit, Nekrasovit, Ovamboit and Stibiocolusit a subset of the sulphides of zinc, iron, copper or silver.

In the classification by Dana it forms with Renierite, Maikainit and Ovamboit a subset of the sulfides, selenides and tellurides with the composition AmBn Xp, with (m n): p = 1:1.

Education and Locations

Germanite forms in primary copper-lead -zinc ores. It is associated with Renierite, pyrite, tennantite, enargite, galena, sphalerite, digenite, bornite and chalcopyrite.

From the very rare mineral only a few localities are known. In addition to the type locality was found germanite in Andalgalá in Argentina, Dastakert in Armenia, Panagjurischte in Bulgaria, the Pinar del Rio province on Cuba, Kipushi in the Democratic Republic of the Congo, Orivesi in Finland, Guillaume in France, Laurion in Greece, Hida and other places in Japan, Niari in the Republic of Congo, Magnitogorsk and other localities in Russia and the U.S. states of Alaska and Colorado.

Crystal structure

Germanite crystallizes in the cubic crystal system in space group P43n with the lattice parameters a = 10.59 Å and two formula units per unit cell.