χαλκηδων , Revelation 21:19; a precious stone. Arethas, who has written an account of Bithynia, says that it was so called from Chalcedon, a city of that country, opposite to Byzantium; and it was in colour like a carbuncle. Some have supposed this also to be the stone called כפכּ? , translated "emerald," Exodus 28:18 .