Argentopyrite - Encyclopedia

Class : Sulfides and sulfosalts
Subclass : Sulfides
Crystal System : Orthorhombic
Chemistry : AgFe₂S₃
Rarity : Uncommon to rare

Argentopyrite is an iron and silver sulfide present in hydrothermal silver-bearing and often nickel-bearing veins. Quite rare, argentopyrite is the dimorph of sternbergite. Its name comes from the Latin argentum and pyrite in connection with its chemical composition. It occurs in small, thick, pseudohexagonal tabular prisms, frequently united in botryoidal encrustations or radiate aggregates. It is a steel-gray to pewter-white colored mineral when fresh, dulling to dark bronze, dark blue, and purple. It is an accessory ore of silver.

Main photo : Argentopyrite from Schneeberg, Saxony, Germany © Christian Rewitze

Argentopyrite from Freiberg, Saxony, Germany © Joy Desor

Argentopyrite from Sauberg Mine, Saxony, Germany © Stephan Wolfsried

Argentopyrite from Bad Schlema, Saxony, Germany © Stephan Wolfsried

Argentopyrite from Svornost Mine, Czech Republic © Uwe Haubenreisser

Argentopyrite in the World

Argentopyrite seems to be a specific mineral of the Ore Mountains (Erzgebirge) of Central Europe : it is indeed mainly present in millimetric crystals in St-Andreasberg, Schneeberg, Marienberg and Freiberg in Germany ; Medenec, Pribram and Jachymov in the Czech Republic. However, it is also present in a few other sites, notably in Broken Hill (Australia) and Colquechaca (Bolivia).

Argentopyrite in France

In France, argentopyrite is found in microcrystals at the Gabe Gottes Mine near Ste-Marie-aux-Mines (Haut-Rhin).

Twinning and special crystallizations

Argentopyrite may exhibit pseudohexagonal and lamellar twins.

Fakes and treatments

No fake or treatments identified for this mineral species.

Hardness : 3.5 to 4
Density : 4.25
Fracture : Irregular
Trace : Gray

TP : Opaque
RI : -
Birefringence : -
Optical character : -
Pleochroism : None
Fluorescence : None

Solubility : Nitric and hydrochloric acid

Magnetism : None
Radioactivity : None