Harmotome

Harmotome
240px Harmotome
General
Category	zeolites
Formula (repeating unit)	(Ba0.5,Ca0.5,Na,K)5Al5,Si11O32·12(H2O)

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.

Name and discovery

Named from the Greek words harmos (a joint) and temseis (I cut) because the pyramid divides parallel to the plane that passes through the terminal edges. It was first described in 1801 from an occurrence in the Harz Mountains, Lower Saxony, Germany.

References

• Mindat w/ locations
• Webmineral
• Dictionary.com