Source : Webster's Revised Unabridged Dictionary (1913)

Aquamarine \A`qua*ma*rine"\, n. (Min.)
   A transparent, pale green variety of beryl, used as a gem.
   See {Beryl}.

Source : WordNet®

aquamarine
     n 1: a transparent variety of beryl that is blue green in color
     2: a shade of blue tinged with green [syn: {greenish blue}, {aqua},
         {turquoise}, {cobalt blue}, {peacock blue}]