Black onyx is believed to be one of the most powerful protection stones. Black onyx is associated with the base (root, first) chakra.  Black Onyx has the ability to soothe fears and worries, to control to overwhelming emotions. Onyx can help a person maintain a positive outlook while awaiting the result of a source of anxiety. Onyx is recommended for improving concentration and devotion, calming sexual tension and ending marital disputes. Black Onyx helps to remove depression, nightmares and losses in legal matters.