Obsidian is a naturally occurring volcanic glass that forms when lava cools rapidly. It is usually black or dark brown in color and has a smooth, shiny surface. Obsidian was used by ancient civilizations for making tools, weapons, and decorative objects. In modern times, it is used for jewelry, sculpture, and as a material for surgical scalpels. Obsidian is also believed to have metaphysical properties and is used in healing and meditation practices.
