The Collaborative International Dictionary of English v.0.48:

Tiger-eye \Ti"ger-eye`\, n. (Min.)
   A siliceous stone of a yellow color and chatoyant luster,
   obtained in South Africa and much used for ornament. It is an
   altered form of the mineral crocidolite. See Crocidolite.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Crocidolite \Cro*cid"o*lite\ (kr?-s?d"?-l?t), n. [Gr. kroky`s
   nap on cloth + -lite.] (Min.)
   A mineral occuring in silky fibers of a lavender blue color.
   It is related to hornblende and is essentially a silicate of
   iron and soda; -- called also blue asbestus. A silicified
   form, in which the fibers penetrating quartz are changed to
   oxide of iron, is the yellow brown tiger-eye of the
   jewelers.
   [1913 Webster]