Stephanite

From the Mun. de Fresnillo area in the state of Zacatecas, Mexico, a stunning miniature of lustrous metallic grey Stephanite crystals in an open form, so displaying individual crystals to their best advantage.  Intergrown crystals of Stephanite measure to 1 cm with striated prism faces and pinacoid terminations, some crystals displaying multiple terminations.  Small areas are dusted with micro-crystallised, biscuit coloured Siderite.  Stephanite is a relatively rare silver sulphosalt and can often form as more massive or poorly defined crystals, certainly not the case in this specimen.  It is mounted on a small bevelled acrylic base and comes with an Arizona-Sonora Desert Museum Earth Sciences label, #1026.