Your fossil could be a fish tooth. During the Carboniferous period, about 300 million years ago, lots of fish lived in the swamps which covered the area which is now Stoke-on-Trent. Some of these fish periodically shed their teeth, as modern sharks do, and these teeth were often fossilised. In the area that is now the Potteries it is quite common to find fish teeth preserved in coal.
Fish tooth fossils are often distinctive enough and well enough preserved to identify which species of fish they came from. If you want to try and identify your fish tooth fossil more precisely, you could search the Virtual Store or could take it to your local museum to be identified.
Click here to search the Virtual Store.