[ noun ] a chalcedony with alternating black and white bands; used in making cameos <noun.substance>
Onyx \O"nyx\, n. [L., fr. Gr. ? a claw, finger nail, a veined gem. See {Nail}, and cf. {Onycha}.] 1. (Min.) 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.
2. Same as {Mexican onyx}. [PJC]
3. A deep jet-black color. [PJC]
{Onyx marble}, {Mexican onyx}, a banded variety of marble or calcium carbonate resembling onyx. It is obtained from Mexico in various colors ranging from white to deep black. [1913 Webster +PJC]
onyx \o"nyx\, a. Deep, jet-black. [PJC]
Onycha \On"y*cha\, n. [NL., from L. onyx, -ychis, onyx, also, a kind of mussel, Gr. ?, ?. See {Onyx}.] 1. An ingredient of the Mosaic incense, probably the operculum of some kind of strombus. --Ex. xxx. 34.
2. The precious stone called {onyx}. [R.]
Chalcedony \Chal*ced"o*ny\ (k[a^]l*s[e^]d"[-o]*n[y^] or k[a^]l"s[-e]*d[-o]*n[y^]; 277), n.; pl. {Chalcedonies} (-n[i^]z). [ L. chalcedonius, fr. Gr. CHalkhdw`n Chalcedon, a town in Asia Minor, opposite to Byzantium: cf. calc['e]doine, OE. calcidoine, casidoyne. Cf. {Cassidony}.] (Min.) A cryptocrystalline, translucent variety of quartz, having usually a whitish color, and a luster nearly like wax. [Written also {calcedony}.]
Note: When chalcedony is variegated with with spots or figures, or arranged in differently colored layers, it is called {agate}; and if by reason of the thickness, color, and arrangement of the layers it is suitable for being carved into cameos, it is called {onyx}. {Chrysoprase} is green chalcedony; {carnelian}, a flesh red, and {sard}, a brownish red variety. ※ ||
Using material left over from his sculpture work, Agid has lovingly etched more than 600 mineral missives out of onyx, marble and granite.
Famous for its unique onyx staircase, it has housed the Travelers' Club since the early 1900s and can be visited by appointment.