Orange copper

Native copper is copper in its pure, uncombined metallic state, which is rare among metals. It occurs naturally as a mineral, often with a reddish-brown color that can tarnish green, and is found in forms like nuggets, wires, or irregular masses. This type of copper was one of the first metals used by humans for tools and jewelry because it could be extracted directly from the earth.  It is an excellent conductor of heat and electricity, second only to silver.

The largest and most famous deposits of native copper in the world are found in the Keweenaw Peninsula of Michigan, USA, where massive quantities (some single masses weighing hundreds of tons) were mined historically.