Native Michigan copper can occur in veins, as spots, streaks or large masses. The copper slabs feature copper-rich ore with quartz, basalt, epidote, and calcite. Each slab is uniquely individual based on the configuration of the copper itself and the mineral content of the host rock.
Additionally, a novel source of copper is from the refineries that were in operation from 1845 through 1982. As the copper ore was refined the molten copper penetrated the fire bricks an created an anomaly that makes very interesting lapidary material.