Chalcedony is the name of a group of stones including carnelian, jasper, heliotrope and chrysoprase, as well as the stone chalcedony. Chalcedony is a bluish-white-grey stone that probably takes its name from an ancient city on the Bosporus. In contrast to crystals that shine like glass, such as rock crystal, it is usually waxy or matt. Today it is mostly used as a material for cameos, ring stones, seal stones and for stone chains. It has been processed for a long time and is therefore often found in antiques. Large pieces are also used to make columns, table tops and vases. Chalcedony is found in Brazil, Namibia, Madagascar and India.