Onyx is a chalcedony quartz. The name comes from the Greek word "onyx" which means nail of a finger or claw. Legend says that one day while Venus was sleeping Eros/Cupid cut her fingernails and left the clippings scattered on the ground. Because no part of a heavenly body can die, the gods turned them into stone which later became known as onyx.

Onyx has a fine texture and black color. Some onyx also displays white bands or ribbons against a black or brown background and this variety is known as sardonyx.

Onyx may be found in Brazil, India, California and Uruguay.