Carnelian or cornelian is a reddish brown chalcedony. In ancient Rome, it was often used in cameos and intaglios . Chrysocolla quartz is chalcedony mixed with varying amounts of chrysocolla . The chrysocolla provides the robin's egg blue coloration, and the quartz provides sufficient hardness for use in jewelry. The durability varies with the corresponding proportions of the two components.
Chrysoprase is a light to medium, slightly yellowish green chalcedony.
Australia provides many of the finest examples. Fire Agate is chalcedony that contains many layers of tiny inclusions of limonite or goethite, which produce a distinctive firelike iridescence when properly cut to leave only thin protective layers of chalcedony over the inclusions. Many of the finest specimens have been found in Arizona. Jasper , in contrast to chalcedony , is an opaque and more coarsely grained cryptocrystalline quartz. Like chalcedony, it may be patterned or uniform in color.