Mohawkite

Mohawkite is a rare, naturally occurring copper alloy, primarily a mixture of copper and arsenic. It is found almost exclusively in Michigan's Keweenaw Peninsula and is named after the Mohawk Mine where it was discovered. It is valued for its metallic luster, appearing brassy-yellow to gray with potential blue or green tarnish, often with spiderweb patterns in white quartz, and is used as a gemstone or collector's mineral for its unique beauty and perceived spiritual properties like willpower.