A translucent chalcedony usually consisting of straight, parallel bands and colored black and white in alternating layers.

Onyx is said to have been one of the stones used in the breastplate of the ancient high priest. For hundreds or years, it was carved to produce cameos as the contrast between the different colored layers heightened the relief. It has been used to alleviate grief, promote self control and wise decision making and to bring happiness and good fortune. It is considered to be useful in the treatment of heart trouble, ear/hearing problems, watery eyes, hair problems and disorders related to bone marrow. It is thought to relieve stress by enhancing self control and inspiring serenity.