This is a fine and very interesting ore specimen consisting of Pyrite and Acanthite. This large matrix features a bunch of vugs, lined with finest wires and "wool balls" of native Silver. They are nicely burnished with a beautiful natural patina. On the whole specimen you can see with magnification small needle shaped Acanthite crystals. This is definitely an indicator of the richness of silver in the matrix. A super specimen from the older times of Fresnillo.