The Collaborative International Dictionary of English v.0.48:

Cymophane \Cym"o*phane\ (s?m"?-f?n or s?"m?-), n. [Gr. ??? wave
   + ??? To appear: cf. F. cymophane. So named in allusion to a
   peculiar opalescence often seen in it.] (Min.)
   See Chrysoberyl.
   [1913 Webster]