The Collaborative International Dictionary
Harmotome \Har"mo*tome\ (-m[-o]*t[=o]m), 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.
Note: A related mineral, called lime harmotome, and
Phillipsite, contains lime in place of baryta.
n. (context mineral English) A rare zeolite, a hydrated barium silicate that forms vitreous white monoclinic crystals.
Harmotome is a mineral, one of the rarer zeolites; a hydrated barium silicate with formula: ( Ba, Ca, Na, K) Al, Si O·12( HO). It forms vitreous white well defined monoclinic crystals, often associated with calcite and other zeolites. It has a Mohs hardness of 4 to 5 and a specific gravity of 2.44 to 2.5.