- 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.
Definition
[ n.]