This piece is from Fresnillo in the Mun. de Fresnillo, Zacatecas, Mexico. This locale contains 50 different mineral species including pyrargyrite. It is a silver sulfide that contains the elements Ag, Sb, and S. This specimen consists of a peaked cluster of complex silver-black to reddish crystals that have a sub-metallic luster. There is minor pyrite associated with the piece at its base. This is a thumbnail sized piece that measures 16 x 12 x 10 mm.