Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. Obsidian is produced when felsic lava extruded from a volcano cools rapidly with minimal crystal growth. Obsidian is truth-enhancing. A strongly protective stone, it forms a shield against negativity. Black Obsidian Stone is a powerful cleanser of psychic smog created within your aura, and is a strong psychic protection stone. It blocks psychic attack and absorbs negative energies from the environment. Obsidian draws out mental stress and tension. This stone has powerful metaphysical properties that will help to shield you against negativity. The energy of these stones may stimulate the gift of prophesy.