Topaz

n.
  1. (Min.) A mineral occurring in rhombic prisms, generally yellowish and pellucid, also colorless, and of greenesh, bluish, or brownish shades. It sometimes occurs massive and opaque. It is a fluosilicate of alumina, and is used as a gem.
  2. (Zoöl.) Either one of two species of large, brilliantly colored humming birds of the genus Topaza (Topaza pella or Topaza pyra), of South America and the West Indies.
    3. False topaz . (Min.)
    See the Note under Quartz.