Green beryls are called emerald, blue aquamarine. Green emerald expresses faithfullness and continuity. http://www.sndgems.com/emerald-rings.htm

A precious stone of a rich green color, a variety of beryl. See Beryl.

Of a rich green color, like that of the emerald.

It is the green colored beryl and among gemstone it is one of the most valuable one. It is the birthstone for the month of May.