Black Onyx crystal necklace. Black Onyx. A powerful protection stone, Black Onyx absorbs and transforms negative energy, and helps to prevent the drain of personal energy. Black Onyx aids the development of emotional and physical strength and stamina, especially when support is needed during times of stress, confusion or grief. Specifications: *Pendant size : approx. 25 mm*Black Plated Brass chain length : approx. 45 cm