Double Calymene Celebra Trilobite

This is a natural double of the trilobite Calymene celebra from Illinois. These trilobites used to be fairly common, but over the decades the quarries they were collected from closed one by one and as far as I know new ones haven't come onto the market in years. This is a fine specimen, preserved as an internal mold in Dolostone.

Calymene celebra is the state fossil Wisconsin in 1985.