Petoskey Stones, the state stone of Michigan, are fossilized coral resulting from glaciation and are often polished to reveal the beautiful pattern of the 6 sided coral colonies. #Geology #Petoskey_Stone #Michigan
Petoskey Stones were formed by the fossilization of ancient coral, Hexagonaria. The coral lived in shallow waters. Petoskey Stones are found on many beaches of Lake Michigan and Lake Huron, as well as in rock quantities from Traverse City to Alpena. The honeycomb patterned stone has a hardness from 4 to 5.
A Petoskey stone is a rock and a fossil, often pebble-shaped, that is composed of a fossilized coral, Hexagonaria percarinata. They are fragments of a coral reef that was originally deposited during the Devonian period, about 350 million years ago. (Wikipedia) Photo by Mark Willocks.