The “petoskey stone”, which can be collected on the western banks of the Lake Michigan, is usually not an agate, but a polishable devonic-aged limestone with fossil relics of corals, from “Hexagonaria percarinata”. They produce a popular honeycomb pattern on the surface of the polished stone. The name “Petoskey stone” was derived from the name of the Ottawa chieftain Petosegay.