An amazing thumbnail specimen. Sought after for the species (a silver mineral) and for the locality (the famous San Juan de Rayas Mine). A cluster of crystals with very little Calcite in between.
As is very often the case, this Pyrargyrite is much better in person when you can hold a torch to it and see if it does the "red thing", the deep red internal glow. Get it before it graces someone else´s collection.