Beryl (βήρυλλος [Revelation 21:20], a word of unknown etymology) is a mineral which differs little from the emerald except in colour. It never exhibits the deep rich green of that gem, being in general pale green, and sometimes yellowish, bluish, brownish, or colourless. Its finer varieties, which are transparent, are called aquamarine. It usually takes the form of long six-sided prisms, vertically striated. It was much prized as a gem-stone by the ancients, and very fine specimens of Greek and Roman engraving in beryl are extant. Its great abundance in modern times has depreciated its value. In Revised Version margin of the OT, ‘beryl’ stands for shôham, which Flinders Petrie (Hasting's Dictionary of the Bible (5 vols) iv. 620b) identifies with green felspar.
James Strahan.