In jewelry design as in fashion, colors look crisper against a background of black and black and white always looks right. In fine jewelry, the black backdrop is often supplied by onyx, a chalcedony quartz with a fine texture and black color. Some onyx also displays white bands or ribbons against a black background. If the layers are even, this type of onyx can be carved into cameos.
Black onyx shines when used as a backdrop for color play. Its fine texture also makes it ideal for carving, which makes it a favored material for lapidary artists. Onyx was often used as the perfect foil for carved rock crystal or the red of rubies in Art deco designs. It is also popular in marcasite jewelry.
Onyx was very popular with the ancient Greeks and Romans. The name comes from the Greek work onux, which means fingernail. Even though black isn’t usually the color you would associate with fingernails, in Greek times, almost all colors of chalcedony from fingernail white to dark brown and black were called onyx. Later, the Romans narrowed the term to refer to black and dark brown colors only.