1) Beautiful stone 2) Chrysoberyl 3) Cut mineral 4) Decorative stone 5) Gemstone 6) Gemstone mineral 7) Jewel mineral 8) Jewel 9) Mineral gemstone 10) Mineral jewel 11) Polished mineral 12) Polished jewel 13) Precious gem 14) Prized stone 15) Precious jewel 16) Precious stone 17) Prized mineral 18) Precious gemstone Found on https://www.crosswordclues.com/clue/cymophane
Cym'o·phane noun [ Greek ......... wave + ......... To appear: confer French cymophane . So named in allusion to a peculiar opalescence often seen in it.] (Min.) See Chrysoberyl . Found on http://www.encyclo.co.uk/webster/C/210