The Collaborative International Dictionary of English v.0.48:

Eudialyte \Eu*di"a*lyte\, n. [Gr. e'y^ well, easily + ? to
   dissolve. So called because easily dissolvable in acids.]
   (Min.)
   A mineral of a brownish red color and vitreous luster,
   consisting chiefly of the silicates of iron, zirconia, and
   lime.
   [1913 Webster]