Chalcedony is a fine-grained member of the quartz family, similar in appearance to nephrite jade. It has no distinguishing characteristics, but it may be found in a wide variety of colors, among them the gemstone varieties known as jasper and agate.
Two other ornamental varieties of chalcedony are carnelian, which has a deep reddish-brown color, and bloodstone, which is green with red flecks. Pale chalcedonies are often dyed, and usually appear unnatural.
