Obsidian is formed when volcanic lava comes into contact with water; this forces it to cool so quickly that it doesn’t have time to crystallize resulting in a stone with a shiny, glassy texture.
Black Obsidian is an extremely powerful and fast acting stone, and should be used with caution for Crystal Healing. It can bring negative emotions and unpleasant truths rushing to the surface, which have to be confronted before peace can return. Many people find Obsidian’s effects overwhelming and prefer to use a gentler stone.
Black Obsidian is a very protective stone. It is said to form a shield against negativity and to absorb negative energies from the environment. Because of this it should be cleansed regularly in running water.