Isle Royale greenstone, this state's official gem, is found on Isle Royale in Lake Superior
Native silver is found in association with the native copper deposits of the 
Keweenaw... [DOC] [TLE] The Two Greenstones of Lake Superior - Lake Superior Magazine [PAR] Feb 1, 1999 ... Isle Royale Greenstone, the mineral, can be found in a belt ... [DOC] [TLE] Isle Royal greenstone - State of Michigan [PAR] pumpellyite.