Michigan's Keweenaw Peninsula is considered the most important locality in the world for pure native copper Mining began in 1845 and continued through 1982, and over 7 million tons of refined copper were recovered from the mines. At the turn of the 20th century it led the world in copper production and "Lake Copper" was the purity standard. The chemical symbol for copper is Cu.

Shiny copper heart
1.75" wide