Source : Webster's Revised Unabridged Dictionary (1913)

Beryl \Ber"yl\ (b[e^]r"[i^]l), n. [F. b['e]ryl, OF. beril, L.
   beryllus, Gr. bh`ryllos, prob. fr. Skr. vai[dsdot][=u]rya.
   Cf. {Brilliant}.] (Min.)
   A mineral of great hardness, and, when transparent, of much
   beauty. It occurs in hexagonal prisms, commonly of a green or
   bluish green color, but also yellow, pink, and white. It is a
   silicate of aluminium and glucinum (beryllium). The
   {aquamarine} is a transparent, sea-green variety used as a
   gem. The {emerald} is another variety highly prized in
   jewelry, and distinguished by its deep color, which is
   probably due to the presence of a little oxide of chromium.

Source : WordNet®

beryl
     n : the chief source of beryllium; colored transparent varieties
         are valued as gems