What does "chalcedony" mean?

Chalcedony: A cryptocrystalline, translucent variety of quartz, having usually a whitish color, and a luster nearly like wax. [Written also calcedony.] Note: When chalcedony is variegated with with spots or figures, or arranged in differently colored layers, it is called agate; and if by reason of the thickness, color, and arrangement of the layers it is suitable for being carved into cameos, it is called onyx. Chrysoprase is green chalcedony; carnelian, a flesh red, and sard, a brownish red variety.