Fettellite is an extremely rare silver species. This is one of just a very few specimens to turn up at the Denver show amidst literally hundreds of proustites for sale, this is a huge and rich piece loaded with Fettelite! The crystals form sharp blades to 3 mm and are easily eye-visible in larger clusters. The specimen could probably be broken up into a dozen pieces, each with both fettelite and proustite.