Onyx /(?)/

O·nyx

Onyx

n.
  1. Chalcedony in parallel layers of different shades of color. It is used for making cameos, the figure being cut in one layer with the next as a ground. (Min.)
  2. Same as Mexican onyx.
  3. A deep jet-black color.

Phrases & Compounds
Onyx marble
a banded variety of marble or calcium carbonate resembling onyx. It is obtained from Mexico in various colors ranging from white to deep black.

onyx

a.
  1. Deep, jet-black.