Chalcedony

Chalcedony is a group of transparent gemstones that can range in a wide variety of colours. It includes Agate, Aventurine, Carnelian and Onyx. The term chalcedony is derived from the name of the ancient Greek town Chalkedon in modern Turkey. As early as the Bronze Age chalcedony was in use in the Mediterranean region; for example, in Minoan Crete, chalcedony seals have been recovered dating to 1800BC. People living along the Central Asian trade routes used various forms of chalcedony, including Carnelian, to carve intaglios, ring bezels (the upper faceted portion of a gem projecting from the ring setting), and beads that show strong Greco-Roman influence. See Aventurine, Carnelian and Onyx.