This fossil and mineral combination specimen features a striking, complete, 360 degree pyrite cluster sitting atop the open end of the original animal, 3.5 cm tall. The stalk of the fossil is another 6.5 cm long, and has a great color and luster to it, with minor secondary pyrite growths at the far end. This is a striking display specimen both as a fossil or as a mineral! These formed from simple chemical processes over time as with several other famous finds of mineralized fossils, given the right conditions in the ground as the soft mud turns to soft stone and then hard stone that entombed the pyrite within: decaying organic matter (the Baculite) provided the Sulfur necessary to react with iron in the environment (likely water rich in iron trickling down when the rock was still porous) and caused iron sulfides (Pyrite) to precipitate and force their way out into the stone as they grew, followed by the whole thing being preserved in rock. All of the pyrite found here is actually associated with the same process, even if you do not see a fossil with it (it would have nucleated the pyrite cluster, in any case). These particular specimens represent some of the best of the best of the best, found over 40 years of painstaking searching and filling trucks with ugly black rock to see what is inside, collected by amateur paleontologist and mineral preparator Bill Hawes. They have been expertly worked out of the encasing stone to show the beauty within and make for fabulous mineral/fossil specimens that are simply unique to this location. Please note, due to the physical process of removing the rock carefully around the pyrite, that the specimens are repaired and/or stabilized.