Sar'donyx (σαρδόνυξ, from σάρδιον, the sardius, and ὄνυξ, the onyx) is mentioned in the New Test. once only — viz. in Re 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).
The Cyclopedia of Biblical, Theological, and Ecclesiastical Literature was edited by John McClintock and James Strong. It contains nearly 50,000 articles pertaining to Biblical and other religious literature, people, creeds, etc. It is a fantastic research tool for broad Christian study.
John McClintock was born October 27, 1814 in Philadelphia to Irish immigrants, John and Martha McClintock. He began as a clerk in his father's store, and then became a bookkeeper in the Methodist Book Concern in New York. Here he converted to Methodism and considered joining the ministry. McClintock entered the University of Pennsylvania in 1832 and graduated with high honors three years later. Subsequently, he was awarded a doctorate of divinity degree from the same institution in 1848.WikipediaRead More