These acanthite crystals are from the San Juan de Rayas Mine in Guanajuato, Mun. de Guanajuato, Guanajuato, Mexico. This is a gold and silver mine that contains 16 different minerals including acanthite. It is a silver sulfide containing the elements Ag and S. This piece is a pseudomorph or replacement of argentite crystals with acanthite. It has intact crystals on all sides and it displays nicely from any side or angle. The primary crystal is hoppered or has skeletal habits. They have a silver-grey color.and sub-metallic luster. This is a thumbnail sized piece and it measures 23 x 20 x 11 mm.