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 Stones are unique rocks and fossils, specifically the fossilized rugose coral Hexagonaria percarinata. Typically pebble-shaped, these stones are found primarily in the northwestern and northeastern regions of Michigan's Lower Peninsula. They are remnants of an ancient coral reef that thrived during the Devonian period, approximately 350 million years ago.

Petoskey stones were formed through glacial activity, when ice sheets plucked them from the bedrock, smoothing rough edges and depositing them in new locations. When dry, these stones may appear to be ordinary limestone, but when wet or polished, they reveal a distinctive mottled pattern of six-sided coral fossils. Each fossil consists of tightly packed, six-sided corallites, which are the skeletal remains of once-living coral polyps. The center of each polyp housed the mouth, with tentacles that extended outward to capture food. The hexagonal shape of each cell and the thin lines radiating from the dark central “eye” are unique features that make Petoskey stones instantly recognizable.

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 farmers' fields. The best time to find them is often in the spring after the ice has shifted the shoreline.