A natural volcanic glass, obsidian is formed by the rapid cooling of volcanic magmas. Typically jet black, this igneous rock also comes in many varieties such as mahogany, snowflake, sheen, spider web, and rainbow. Obsidian’s conchoidal fracture makes it easily chipped to form razor-sharp edges. It was used by many ancient cultures to make weapons, tools, and ornaments. Metaphysically, obsidian is used for protection and the releasing of negative energy. Major deposits of obsidian are found in the USA, Mexico, Japan, and Iceland.