Acanthite

Template:Short description Template:Infobox mineral Acanthite is a form of silver sulfide with the chemical formula Ag₂S. It crystallizes in the monoclinic system and is the stable form of silver sulfide below Template:Convert. Argentite is the stable form above that temperature. As argentite cools below that temperature its cubic form is distorted to the monoclinic form of acanthite. Below 173 °C acanthite forms directly.<ref name=Handbook/><ref name=Klein/> Acanthite is the only stable form in normal air temperature.

Occurrence

Acanthite is a common silver mineral in moderately low-temperature hydrothermal veins and in zones of supergene enrichment. It occurs in association with native silver, pyrargyrite, proustite, polybasite, stephanite, aguilarite, galena, chalcopyrite, sphalerite, calcite and quartz.<ref name=Handbook/>

Acanthite was first described in 1855 for an occurrence in the Jáchymov (Joachimsthal) district, Ore Mountains, Bohemia (today Karlovy Vary Region, Czech Republic). The name is from the Greek "akantha" meaning thorn or arrow, in reference to its crystal shape.<ref name=Mindat/><ref name=Webmin/><ref name=Klein/>

Gallery

• Acanthite - Chispas Mine, Arizpe, Sonora, Mexico.jpg

  Acanthite. Locality: Chispas Mine, Arizpe, Sonora, Mexico. Scale is one inch with a ruled line at one cm.

• Acanthite-180757.jpg

  Classic acanthite specimen from the Rayas Mine at Guanajuato, Mexico. Size: 2.4 × 1.1 × 1.1 cm.

See also

• List of minerals