This specimen of Coronadite is from the Defiance Mine in Arizona and is world class for the species. It is also a large display quality piece for the species and consists of a sculptural bubbly surface of metallic-gray Coronadite, an uncommon Pb-Mn oxide. The botryoids are tightly grown together and range from 0.5 to 2 cm across with a satin luster and a moderately rough surface. Excellent, rare and desirable material. Bob Bartsch collected the specimen on August 2, 1964. It was X-Rayed by John Attard. Rock Currier got the specimen when he was given Bob's collection in his living trust. http://www.mindat.org/article.php/2158/Robert+Bartsch+++RIP++1939+to+2014. An unusual addition to any Arizona or USA collection!