Acanthite

Classic acanthite specimen on matrix from the historic silver mining district of Annaberg-Buchholz, Erzgebirge, Saxony, Germany. The specimen shows dark grey to black acanthite forming compact crystalline aggregates on a light-colored gangue matrix, typical for Erzgebirge silver vein mineralization.

Acanthite is the low-temperature polymorph of silver sulfide (Ag₂S) and represents the stable form of argentite at ambient conditions. Many specimens preserve pseudocubic crystal shapes, reflecting inversion from high-temperature argentite during cooling.

The Erzgebirge is one of Europe’s most important historical silver mining regions, and acanthite from Annaberg-Buchholz is regarded as classic reference material for German silver deposits. Matrix specimens are particularly valued by locality and systematic collectors.

Acanthite forms in hydrothermal silver-bearing veins, commonly associated with carbonate and quartz gangue. The mineral is stable under normal collection conditions.

Typical associated minerals at Annaberg-Buchholz include calcite, quartz, galena, sphalerite, native silver, and other silver sulfides and sulfosalts.