Throughout history, onyx has been thought to bring powers of protection, defensive magic, and the reduction of sexual desires. It has also been thought to reinforce the knowledge that there is no death, aiding in the understanding of the wheel of birth, death and rebirth. It brings about the knowledge that separation is an illusion and reunion will come. It aids psychic contact with those who have died, facilitates séances and mediumship, brings messages from the dead, and aids past-life and between-lives regression work. It helps future life progressions, and prevents and removes spirit possessions.
Contemporary authors say the onyx brings increased vigor, strength, stamina, and self control. It alleviates worry, tension, and nervousness and eliminates confusion and nightmares. It is used to provide glimpses of that which is ‘beyond’ and activates one’s memory of one’s roots and reality. Medicinal applications include the treatment of bone marrow diseases, teeth, foot, blood and bone problems, and soft tissue disorders. It is also believed to aid in ailments such as epilepsy or glaucoma and is known to have powers to rectify damage done to cells.