Simply put, a Petoskey Stone is an extinct fossilized coral. Why is it called, “Petoskey Stone”? Because they are found in abundance in and around Lake Michigan shores, particularly near the northern Michigan city of Petoskey! The name “Petoskey” is the English adaptation of an Ottawa Indian Chief Petosegay, which is said to mean “The Rising Sun”!

They are also called “lucky stones” by many because finding these ancient coral fossils, remnants of prehistoric reefs, feels like discovering a special piece of history!

How could the remains of coral, which lived in tropical warm ocean waters, possibly find its way to the cool regions of Michigan? To explain – during the prehistoric Devonian Time Period around 416 to 369 million years ago, the landscapes of North America lay nearer to the equator and when Earth’s climate was tropical with little to zero polar icecaps. Consequently, risen, warm, shallow seas covered a large portion of the North American continent, including Michigan where the Petoskey stone “Hexagonaria, percainata” coral thrived. Eventually, the coral faced mass extinction and the coral remains were buried under deep layers of sediment. Many millions of years afterwards, around 15,000 years ago, the great glaciers retreated northward forming the Great Lakes while simultaneously digging deep into those forgotten layers of earth. Ultimately this freed the coral fossils from earth trappings and the glaciers deposited them where we can now enjoy the good fortune of discovering their mysteries.

Petoskey Stone fossils originate from mass coral colonies of Hexagonaria, percarinata. Each hexagonal corallite, visible in the stone, held a single animal possessed of many tentacles. The tentacles siphoned food particles floating by in ocean currents and fed the food to a mouth held in the center of the corallite. The tentacles were also used to sting other organism or corallites that came too close. Calcite, silica and other minerals replaced the original exoskeleton over many millions of years.

PETOSKEY STONE CLASSIFICATION

Common Name: Petoskey Stone or Lucky Stone

Scientific Name: Hexagonaria, percarinata

Kingdom: Animalia

Phylum: Cnidardia (means to sting)

Class: Anthozoa (ie coral, sea pens, sea anemones)

Subclass: Zoantharia (true corals)

Order: Rugosa (means wrinkled wall)

Family: Hexagonaria (means six sides)

Species: percarinata

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