Allargentum is a rare silver antimonide. It is a mineral from the class of antimonides, a superclass of sulfides and sulfosalts (sometimes ascribed to the natural elements and alloys class), with the formula written as Ag1-xSbx, where x = 0.09–0.16. It is not Radioactive. It is named after the Greek word allos, meaning “another” and the Latin word for “silver,” Argentum, in reference to the mineral composition.

This moderately rare mineral is found in silver ores and is therefore named from the Greek (allos, “another”) and the Latin Argentum (“silver”). Its Vickers hardness is 172–203.

General Information

  • Category: Sulfide mineral
  • Formula: Ag1-xSbx
  • Crystal system: Hexagonal


  • Color: Silver gray
  • Mohs scale hardness: 4
  • Luster: Metallic
  • Diaphaneity: Opaque
  • Specific gravity: 10.0 (means.), 10.12 (calc.)


Allargentum is a rare mineral that occurs in high-grade silver-antimony ores in localities in Canada, the United States, Australia, France, the Czech Republic, Germany, Sweden, and Uzbekistan, among only a couple others. Allargentum is associated with silver that contains antimony and mercury, dyscrasite, breithauptite, domeykite, kutinaite, and stephanite.


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