Obsidian is a volcanic glass that occurs when lava from volcanic eruptions cools within the earth. The speed of the cooling process prevents crystallisation resulting in this volcanic glass. Obsidian is commonly black but also light brown, brown mottled with black and black with a beautiful golden or silvery sheen. Snowflake Obsidian is black with white patches where parts of the rock have begun to crystallise. Sometimes Obsidian may still have patterns of gas bubbles from the lava flow, aligned along layers created as the molten rock was flowing before being cooled. These bubbles can produce coloured sheens. Rainbow Obsidian has an iridescent, rainbow-like sheen and Golden Obsidian a golden sheen.
Obsidian was used in ancient times to create early mirrors and to create razor sharp edges for arrows and spears. Obsidian is believed to protect the sensitive against depression and to block negativity. It is believed to draw out mental stress and tension and promote compassion and strength.