unpolished petoskey stone is a rock and fossil, composed of a fossilized rugose coral, hexagonaria percarinata, formed as a result

abstract animal arrangement art background beach beautiful bedrock collect colony coral dead decorative fossil fossilized gem gemstone geometric glaciation glacier hard hexagonaria ice isolated lake landscape lapidary living michigan natural nature pattern pebble percarinata petoskey polished reef rock rugose sided smooth souvenir specimen state stone summer texture travel unpolished white