Caledonia Mine, near Mass, Michigan

The Caledonia Mine operated beginning in 1863 and then had several brief periods of operation until 1958. It is now kept open for collecting mineral specimens.  One specimen of native copper weighed 3000 lbs, and native silver, datolite, calcite, epidote and adularia are also collected here and sold.

map from Bornhorst & Barron, 2012