Here is a rostroconch called Hippocardia cuneus (Conrad, 1840) from the Middle Devonian period. It was found in the Jeffersonville Limestone located in Louisville Kentucky. It is very small at 1 cm in length and about 5 mm wide.
These are not fossils but I took some pictures of the mineral display cases as well at the Cincinnati GeoFair 2009. Here are some pictures of fluorite, sphalerite, and calcite.