This acanthite is from Fresnillo in the Mun. de Fresnillo, Zacatecas, Mexico. This locale contains 50 different mineral species including acanthite. It is a silver sulfide that contains the elements Ag and S. This specimen is an somewhat arborescent cluster consisting of a mix of well defined hoppered acanthite crystals with minor pyrite. It displays nicely either vertically or horozontally (photo 1 and 2 respectively. lt measures 1 1/4 x 3/4 x 3/4 inches or 32 x 19 x 19 mm.