from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A chalcedony that occurs in bands of different colors and is used as a gemstone, especially in cameos and intaglios.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A banded variety of chalcedony, a cryptocrystalline form of quartz.
- adj. jet-black
from the GNU version of the Collaborative International Dictionary of English
- n. 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.
- n. Same as Mexican onyx.
- n. A deep jet-black color.
- adj. Deep, jet-black.
from The Century Dictionary and Cyclopedia
- n. A variety of quartz, closely allied to agate, characterized by a structure in parallel bands differing in color or in degree of translucency: in the better kinds the layers are sharply defined and the colors white with black, brown, or red.
- n. An infiltration of pus between he layers of the cornea, resembling a nail.
- n. In conchology: The piddock, Pholas dactylus.
- n. A razor-shell; a bivalve of the family Solenidæ.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a chalcedony with alternating black and white bands; used in making cameos
The high altar, composed of Mexican marble and onyx, is one of the finest ever constructed.
The onyx was the color of her long, shiny black hair; the rubies were the color of her lips.
It is found notably in the volcanic district of Mono County, and elsewhere, sometimes in the form of Mexican onyx, which is only a translucent variety of the same marble.
Pennsylvania, and Vermont, and also a small amount of so-called onyx marble or travertine obtained from caves and other deposits in Kentucky and other states.
The onyx is a variety of quartz analogous to the agate and other crypto-crystalline species.
Oriental alabaster, the alabastrites of the classical writers, is a translucent marble (calcium carbonate) obtained from stalagmitic deposits; because of its usually banded structure, which gives it some resemblance to onyx, it is also called onyx marble, or simply, though incorrectly, onyx.
It is usually clouded or banded like agate, hence sometimes called onyx marble.
(see Beryl above), we are in no way bound to accept the Greek beryllos as the translation of shhm, and relying on the testimony of the various versions we may safely hold the onyx is the stone signified by shhm.
There is a kind of onyx called a chalcedony, which hath the same qualities,  avails much against fantastic illusions which proceed from melancholy, preserves the vigour and good estate of the whole body.
The shoham stone, rendered "onyx" above, may never be identified.