Look in the mirror at your eyes. Do you see the colored part (iris) with the dark hole (pupil) in the middle? There are some interesting stones that look as though they are covered with little eyes just like yours! These strange-looking objects are called Petoskey (Peh-toss-key) Stones. And they can be found in the shallow waters of certain beaches in northern Michigan. The stones are composed of groups of fossil coral known as Hexagonaria, meaning six-sided, because each little eye has six sides.
Many, many years ago, before dinosaurs and other animals or birds lived on land, it is said that corals were living in the warm shallow seawater covering North America. As time went on, corals formed great reefs in the warm seas and fish became numerous. Later still, the American continent began to rise from the sea, and the first plants, such as mosses and ferns, appeared. That was when the Petoskey Stone coral was most abundant.
There were many kinds of coral living then. Some lived alone, while others gathered in groups called colonies. The Petoskey Stone coral was a colony coral. The stones we see today were formed when the coral animals died and their soft bodies were replaced by a mineral called calcium carbonate. Through the years, this material hardened into limestone, capturing all the tiny details of the original animal.
The Petoskey Stones range in color from a very light brown to a dark gray. Because they have an unusual eye pattern and can be highly polished, they are sought after for jewelry and ornaments, such as letter openers, belt buckles, penholders and figurines. Also, because the Petoskey Stone is found only within its borders, Michigan chose it as its state stone in 1965. This was the first state to select a fossil for such an honor.
If you ever have a chance to visit northern Michigan, be sure to ask if you can stop along one of the beaches. Perhaps you will be lucky enough to find a Petoskey Stone in the shallow water. It may seem to be looking up and saying, “I see you!”