Black onyx, as a protective stone, helps prevent the drain of personal energy while at the same time absorbing and transforming negative energy. It is said that Cleopatra used to wear Black Onyx for its protective features. Sensing negative energy, the crystal would vibrate, alerting the queen of potential danger. This stone is great for banishing grief, enhancing self-control and making wise decisions. It cools and condenses excessive energy and calms nervousness.