star sapphire

star sapphire
    n 1: a sapphire that when cut shows a starlike figure in
         reflected light because of its crystalline structure
    

Sapphire \Sap"phire\ (? or ?; 277), n. [OE. saphir, F. saphir,
   L. sapphirus, Gr. ?, of Oriental origin; cf. Heb.
   sapp[imac]r.]
   1. (Min.) Native alumina or aluminium sesquioxide, {Al2O3};
      corundum; esp., the blue transparent variety of corundum,
      highly prized as a gem.
      [1913 Webster]

            Of rubies, sapphires, and of pearl['e]s white.
                                                  --Chaucer.
      [1913 Webster]

   Note: Sapphire occurs in hexagonal crystals and also in
         granular and massive forms. The name sapphire is
         usually restricted to the blue crystals, while the
         bright red crystals are called Oriental rubies (see
         under {Ruby}), the amethystine variety Oriental
         amethyst (see under {Amethyst}), and the dull massive
         varieties corundum (a name which is also used as a
         general term to include all varieties). See {Corundum}.
         [1913 Webster]

   2. The color of the gem; bright blue.
      [1913 Webster]

   3. (Zool.) Any humming bird of the genus {Hylocharis}, native
      of South America. The throat and breast are usually bright
      blue.
      [1913 Webster]

   {Star sapphire}, or {Asteriated sapphire} (Min.), a kind of
      sapphire which exhibits asterism.
      [1913 Webster]