For some time, these specimens were labeled as being Pyrite coated by "Bravoite." This is completely incorrect, as analysis done by Dr. Pete Modreski at the USGS in Denver, showed that the thin grey coating or "film" on these Pyrite crystals is actually a micro layer of Molybdenite. Please refer to the post on the following link: http://www.mineral-forum.com/message-board/viewtopic.php?t=360. This specimen is a prime example of this material showing textbook pyritohedral form and virtually no damage. Ex. Jaime Bird Collection.