#petoskeystones

We just got in a fresh stock of Petoskey Stones from Michigan. These stones are actually 350 million year old, fossil rugose coral found along the beaches of Lake Michigan, Lake Huron, as well as in rock quarries in the area. Like the fossilization process of other corals, Petoskey stones formed when the polyp of the coral and its openings filled with sand and silt as it petrified. Over time the soft tissue decayed and the calcium carbonate “skeleton” of the colony was replaced by silica, calcite, and other various minerals forming a fossil. The rocks containing this fossil coral were exposed and broken up into smaller pieces by glaciation. These fragments of fossil coral subsequently became rounded and polished due to the action of both glaciers and waves on the lake shores.

https://www.fossilera.com/fossils-for-sale/petoskey-stone