Very nice Clam Shell Fossil from Kerchenskoye Deposit, Kerch, Crimea, Ukraine
These shells normally contain vivianite crystals, but this one is almost empty (just som minor traces of vivianite). However the shell is very well preserved, as a closed shell with intact hinges.
The size is 41 x 43 x 26 mm, and the weight is 55,1 grams.
It is not often you will see this material on the market nowadays. My father aquired this one in the early 2000s.