%harmotome%

n. [ Gr. "armo`s a joint + te`mnein to cut: cf. F. harmotome.] (Min.) A hydrous silicate of alumina and baryta, occurring usually in white cruciform crystals; cross-stone. [1913 Webster]

☞ A related mineral, called lime harmotome, and Phillipsite, contains lime in place of baryta. Dana. [1913 Webster]