Onyx

Onyx is a variety of Agate where the banding lines are straight and parallel, and consistent in band size. Onyx usually refers to material with alternating bands of black and white, but other color combinations exist. Onyx is the name given to Agate of this habit, although banded Calcite or Aragonite of this type may also be called Onyx. The name Onyx may also incorrectly refer to unbanded, solid Chalcedony dyed black. Onyx is carved into ornamental figures, cameos, beads, and cabochons.

See also Sardonyx