This is a fossil fish slab. It originates from the famous Florissant fossil beds in Colorado USA. This formation dates to the Eocene period (approx. 34 million years ago). Florissant produces many fine fish and plant fossils in shale and sandstone.
This slab measures approx. 5 x 3.75 x .5 inches in size and has fossil fish visible on both sides (species not identified). The fish are two different species. Further preparation work may reveal more fossils.
Refer to the photos. The black centimeter cube is shown for scale and is not included. You are purchasing the slab shown. Your purchase will include an ID label.