Harmotome

[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. Dana.

Harmotome

Harmotome is a mineral, one of the rarer zeolites; a hydrated barium silicate with formula: (Ba_0.5,Ca_0.5,Na,K)₅Al₅,Si₁₁O₃₂·12(H₂O). 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.

It was first described in 1801 from an occurrence in the Harz Mountains, Lower Saxony, Germany.

References

• Mindat w/ locations
• Webmineral

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