925 Pure Silver Finger Ring with Black Onyx Stone. Black Onyx crystals can be used for grounding, protection, and self-control, and as a shield against negative energy. Wearing Gemstone Rings will surround your body with positive and healing energies that will prevent any misfortunes coming your way. They can be given as gifts to commemorate special occasions or to express love and affection. Wearing a Stone Finger Ring can be a way to express one’s identity, values, and beliefs.