(n.) 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.
(n.) A yellow carangoid fish of the Atlantic and Gulf coasts (Caranx chrysos), most abundant southward, where it is valued as a food fish; -- called also hardtail, horse crevalle, jack, buffalo jack, skipjack, yellow mackerel, and sometimes, improperly, horse mackerel. Other species of Caranx (as C. fallax) are also sometimes called jurel.