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Petoskey stones are composed
of fossilized skeletons of colony corals which lived their lifespan
in the warm sea waters that at one time
covered all of what is now the beautiful state of Michigan during
ancient Devonian time, some 350 million years ago. Outcrops of
these rocks are restricted to the Little Traverse Bay area near
Petoskey, Michigan. Glaciers that covered Michigan about two
million years ago plucked Petoskey stones as well as many other
kinds of rocks and distributed them over Michigan and surrounding
areas. Most of the Petoskey stones found along beaches and in
gravels have already been rounded and smoothed by glacial and water
action. Many of these are suitable for hand polishing and will
often take a high polish. Occasionally a Petoskey stone will
be found in "rough" form that has not been subjected to smoothing by
glacial or wave action. The sample shown above is a fine
example of a "rough" Petoskey. It was found in the limestone
quarry at Charlevoix. |
