|Glacial Float Copper
Glaciers crossed Michigan’s Upper Peninsula several thousands years ago. They scoured the landscape eroding vast quantities of rock, transporting it, then redepositing it elsewhere. Native Copper, in the form of “Float” nuggets, is found scattered in these sand and gravel deposits. Though they are common in the four-county “Copper Country” area, these nuggets have been found in several adjacent states. Natural oxidation of the copper occurred over the years, giving the copper nuggets a distinctive green patina. Specimens vary from pea size to slabs weighing thousands of pounds.