Michigan Native Copper from Isle Royale
Native copper from Isle Royale, located in Lake Superior, Michigan, is naturally occurring metallic copper found in a nearly pure state, rather than copper that must first be smelted from an ore. Copper occurs within the island's ancient volcanic rocks, including in veins and cavities associated with the Portage Lake Volcanics.
Specimens can display a rich copper-red to reddish-brown metallic color when fresh, often developing darker brown, black, or green oxidation on exposed surfaces. Isle Royale copper is particularly significant because Indigenous peoples mined and worked native copper on the island thousands of years ago. Archaeological evidence includes ancient mining pits, hammerstones, and charcoal associated with copper extraction.
