Onyx primarily refers to the parallel banded variety of the silicate mineral chalcedony. Agate and onyx are both varieties of layered chalcedony that differ only in the form of the bands: agate has curved bands and onyx has parallel bands. The colors of its bands range from white to almost every color. 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.