I found this in South Dakota. I had never found a pyrite ball before but it was suspiciously round and too heavy. That was a cool enough find...... but I just wondered if there might not be something inside. No guts ... no glory. A beautiful crystal filled little gastropod at the heart of the pyrite. Super cool.!! Maybe these are very common but so cool. What kind of age range could we be talking about with something like this. Did the fossil form somewhere else, get washed out of its matrix and then get encased in pyrite. I dont have a clue about that stuff. Thanks for any info.