From the famous early-1980s pocket of crystallized, lustrous ludlamites, considered by many to simply be the best of species, this is a fine matrix thumbnail! It has dramatic isolated crystals to 1.2 cm starkly standing on contrasting matrix. You almost never see these for sale and they remain a historic classic, seldom available. From the award-winning thumbnail collection of Sharon and William Panczner, author of the book Minerals Of Mexico, and last seen and exhibited publicly in the 1960s.