SARDONYX.See Jewels and Precious Stones.
Hastings' Dictionary of the Bible
Edited by James Hastings, D.D. Published in 1909
Sardonyx. A name compounded of sard and onyx, two precious stones, varieties of chalcedony or agate. The sardonyx combines the qualities of both, whence its name. It is mentioned only in Rev_21:20. The sardonyx consists of "a white opaque layer, superimposed upon a red transparent stratum of the true red sard." It is, like the sard, merely a variety of agate, and is frequently employed by engravers for signet-rings.
Smith's Bible Dictionary
By Dr. William Smith.Published in 1863
σαρδονυξ, Rev_21:20. A precious stone which seems to have its name from its resemblance partly to the sardius and partly to the onyx. It is generally tinged with black and blood colour, which are distinguished from each other by circles or rows, so distinct that they appear to be the effect of art.
Biblical and Theological Dictionary by Richard Watson
PRINTER 1849.
sar?dō-niks. See STONES, PRECIOUS.
International Standard Bible Encyclopedia
PRINTER 1915.
Sardo?nyx, a precious stone exhibiting a milk-white variety of the onyx or chalcedony, intermixed with shades or stripes of the sardian (or carnelian); hence the compound name of sardonyx. It is mentioned in Rev_21:20.
The Popular Cyclopedia of Biblical Literature
by John Kitto.
Rev_21:20 (b) The beauty and the value of these stones probably represent the beauty and the value of the nation of Israel (the twelve tribes) in GOD's program of world development. Every blessing we enjoy has come to us through the influence of Israel. These influences were of various kinds and characters, and this fact is represented by the various kinds of stones.
Wilson's Dictionary of Bible Types
press 1957.
Sardonyx
(σαρδόνυξ, from σάρδιον, the sardius, and ὄνυξ, the onyx) is mentioned in the New Test. once only viz. in Rev_21:20 as the stone which garnished the fifth foundation of the wall of the heavenly Jerusalem. By sardonyx, says Pliny (N.H. 37, 6), who describes several varieties, was formerly understood, as its name implies, a sard with a white ground beneath it, like the flesh under the fingernail. The sardonyx consists of a white opaque layer, superimposed upon a red transparent stratum of the true red sard (King, Ant. Gems, p. 9). It is, like the sard, merely a variety of agate, and is frequently employed by engravers for the purposes of a signet ring. It is a species of onyx, distinguished from the common stone of that name by having its different colors, red and white, disposed in alternate bands. But there is another stone so called, whose tint is reddish yellow or orange, with sometimes a tinge of brown (Moore, Anc. Mineral. p. 153).
CYCLOPEDIA OF BIBLICAL, THEOLOGICAL AND ECCLESIASTICAL
press 1895.