Did you know?
The Lake Superior region holds native copper so pure that people were hammering it straight into tools more than 5,000 years ago, long before anyone in the world had learned to smelt metal.
Cuprite can look like a dull dark stone, but its refractive index of 2.85 beats a diamond's. Lit strongly, it shows its true self as ruby copper, glowing a deep crimson from within.
