Petzite with quartz - Sacarîmb, Nagyág, Romania
|Crystal class||Gyroidal (432) |
(same H-M symbol)
|Color||Steel-gray to iron-black, commonly tarnished from bronze-yellow to sooty black; grayish white with a pale bluish tint in polished section|
|Crystal habit||Granular to massive|
|Tenacity||Slightly sectile to brittle.|
|Mohs scale hardness||2.5 - 3|
|Specific gravity||8.7 - 9.14|
The mineral petzite, Ag3AuTe2, is a soft, steel-gray telluride mineral generally deposited by hydrothermal activity. It forms isometric crystals, and is usually associated with rare tellurium and gold minerals, often with silver, mercury, and copper.
The name comes from chemist W. Petz, who first analyzed the mineral from the type locality in S?c?râmb, Transylvania, Romania in 1845. It was described by Wilhelm Karl Ritter von Haidinger in 1845 and dedicated to W. Petz who had carried out the first analyses.
It occurs with other tellurides in vein gold deposits. It is commonly associated with native gold, hessite, sylvanite, krennerite, calaverite, altaite, montbrayite, melonite, frohbergite, tetradymite, rickardite, vulcanite and pyrite.