3.2" Polished Slab Petoskey Stone Hexagonaria Coral Fossil Devonian Age Michigan

Location: Michigan, United States

Weight: 1.6 Ounces   

Dimensions: 3.2 Inches Long, 1.7 Inches Wide, 0.3 Inches Thick 

The item pictured is the one you will receive.

Devonian Age, 350 million years old

Petoskey Stone is a unique rock and fossil, specifically a fossilized rugose coral known as Hexagonaria percarinata. These stones are typically pebble-shaped and are found primarily in the northwestern and northeastern regions of Michigan's Lower Peninsula. They are fragments of a coral reef that existed during the Devonian period, approximately 350 million years ago.

Petoskey stones were formed through glaciation, where ice sheets plucked stones from the bedrock, grinding off their rough edges and depositing them in specific areas.  When dry, they resemble ordinary limestone, but when wet or polished, they reveal a distinctive mottled pattern of six-sided coral fossils. The Hexagonaria percarinata consists of tightly packed, six-sided corallites, which are the skeletons of the once-living coral polyps. The center of each polyp was the mouth and contained tentacles that reached out for food. The hexagon shape of each cell and thin lines radiating out from the dark “eye” in the center are distinguishing features unique to this fossil.

Petoskey stones can be found on various beaches and inland locations in Michigan, with many of the most popular Petoskey stone beaches stretching from Traverse City to Petoskey along Lake Michigan. The movement of the frozen lake ice during the winters is thought to expose new stones each spring. Popular locations for finding these stones include Petoskey State Park, Magnus City Park Beach, and Solanus Mission Beach. Rockhounds also search cut roadbeds, gravel pits, and farmer's fields. The best time to find them is often in the spring after the ice has shifted the shoreline.