Beryl as a gemstone refers to all varieties of the beryl group which are not emerald-green or aquamarine blue. The name is is derived from the greek beryllos, possibly of Indian origin, although the meaning is not known. Many color varieties have special names in the trade. All are resistant to chemicals with the exception of fluoric acid. They are brittle and therefore easily damaged by knocks, have a vitreous luster, and they occur with aquamarine.