About Chalcedony :-Chalcedony is the form of Quartz that is compact and microcrystalline. It occurs in many different forms, colors, and patterns, and many varieties have been used as gemstones since antiquity. Chalcedony occurs in a wide range of varieties. Many semi-precious gemstones are in fact forms of chalcedony.The name chalcedony comes from the Latin chalcedonius (alternatively spelled calchedonius). The name appears in Pliny the Elder's Naturalis Historia as a term for a translucid kind of Jaspis.The name is probably derived from the town Chalcedon in Asia Minor. The Greek word khalkedon also appears in the Book of Revelation (21:19).