The Petoskey Stone: Michigan's Official State Stone

After just one glance, the Petoskey stone tells of Michigan’s long geological history. The stone is the skeleton of fossilized coral colonies that were prevalent in the area 350 million years ago during the Devonian age when Michigan was under warm seas near the equator – something people visiting our fair state in the winter might find hard to fathom.

Pleistocene glaciers picked up the stones from bedrock roughly 2 million years ago and moved them across Michigan. Its scientific name is Hexagonaria percarinata and is found in Alpena limestone. This name indicates the hexagonal patterns seen in the stone which help identify it.

The stone is named after Petoskey, Michigan, the town near where most of them have been found in the northwestern part of the lower peninsula. There is a controversial story associated with the naming of Petoskey. The legend tells of a Frenchman who was adopted by an Ottawa tribe and made chief after he married an Indian princess. Their son was given the name Petosegay which translates roughly to rising sun. The stone was designated Michigan’s state stone in 1965 with Chief Petosegay’s granddaughter present for the official signing with the governor.

This story is disputed by Native Americans as not having any basis in the reality of their culture. If you’re interested in this perspective, you might want to read Lois Beardslee’s excellent article on exploitative myths of northern Michigan.

Petoskey stones are usually found smoothed by the lake waters, but some still have a rough appearance. They can be polished with sandpaper or lapidary equipment, though some of the stones are too porous and brittle for this. To learn to polish Petoskey stones by hand, read this tutorial at RockTumblingSupplies.com.

Quartz is often found in the stone which adds to its luster. When polished, they are made into all forms of jewelry and animal figurines. Many people however appreciate their natural beauty and leave them alone such as the one pictured below that my husband and I photographed at the White River Light Station Museum in Whitehall, Michigan.

The stones can still be found along beaches, in gravel pits and sand dunes.  They have become a hot commodity in gift shops in favorite tourist spots along the western Michigan shoreline.  They can still be found along Lakes Michigan and Huron.   Fossils of the same coral family can by found in several states including Indiana, Illinois, and Ohio and other countries including England and Germany.

Antrim County holds an annual Petoskey Stone Festival celebrating with skipping stone and essay contests as well as a beach hunt to look for stones. For more information, visit the official website.

Reference:

• Michigan Department of Environmental Quality. The Petoskey Stone.