|—n , pl -nies|
|a microcrystalline often greyish form of quartz with crystals arranged in parallel fibres: a gemstone. Formula: SiO2|
|[C15: from Late Latin chalcēdōnius, from Greek khalkēdōn a precious stone (Revelation 21:19), perhaps named after Khalkēdōn Chalcedon, town in Asia Minor]|
|chalcedony (kāl-sěd'n-ē) Pronunciation Key
A type of quartz that has a waxy luster and varies from transparent to translucent. It is usually white, pale-blue, gray, brown, or black and is often found as a lining in cavities. Agate, flint, and onyx are forms of chalcedony. Chemical formula: SiO2.
Mentioned only in Rev. 21:19, as one of the precious stones in the foundation of the New Jerusalem. The name of this stone is derived from Chalcedon, where it is said to have been first discovered. In modern mineralogy this is the name of an agate-like quartz of a bluish colour. Pliny so names the Indian ruby. The mineral intended in Revelation is probably the Hebrew _nophekh_, translated "emerald" (Ex. 28:18; 39:11; Ezek. 27:16; 28:13). It is rendered "anthrax" in the LXX., and "carbunculus" in the Vulgate. (See CARBUNCLE.)