An exceptional locality specimen , fossil clam with calcite crystals from Ruck’s pit in Okeechobee, FL.  These clams were buried under a tidal wave and are incredibly preserved.  The mine is closed, but the owner stockpiled a bunch of material.  you can make a reservation to dig there, they bring out sand with a Bobcat and dump it in piles.  Hess are provided and the collector merely has to rinse the sand off the rocks to find these amazing fossils.