Hematite

Hematite is best known as one of the main iron ores. Hematite is usually seen as a dark black, brown or red dull to metallic mineral, but it also is seen in a shimmering form called Specular Hematite, and a rare naturally rainbow iridescent form called Rainbow Hematite. This crystal was thought by the Romans to protect them, so the soldiers crushed it and rubbed it on their bodies when they went into battle, whilst Native Americans created war paint with it as it was believed to make them invincible