Black Obsidian Beads Natural, Round, 6 mm, Hole:Approx 1MM. Black Obsidian is thought to be an extremely powerful and fast acting 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. 16-Inch Strand, 1 strand approx 65 pcs