{{Short description|Zeolite mineral}} {{Infobox mineral | name = Gismondine | boxwidth = | boxbgcolor = | image = Gismondina Calatrava.jpg | imagesize = | alt = | caption = Gismondine, Campo de Calatrava, Ciudad Real, Spain | category = Tectosilicate minerals | group = Zeolite group | formula = CaAl<sub>2</sub>Si<sub>2</sub>O<sub>8</sub>·4H<sub>2</sub>O | molweight = | strunz = | dana = 77.1.3.1 | system = Monoclinic | class = Prismatic (2/m) <br/><small>(same H-M symbol)</small> | symmetry = ''P2''<sub>1</sub>/n | unit cell = | color = | colour = | habit = | twinning = | cleavage = | fracture = | tenacity = | mohs = | luster = | streak = | diaphaneity = | gravity = | density = | polish = | opticalprop = | refractive = | birefringence = | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = }} '''Gismondine''' is a mineral with the chemical formula CaAl<sub>2</sub>Si<sub>2</sub>O<sub>8</sub>·4H<sub>2</sub>O. It is a zeolite or hydrated aluminosilicate. It forms colorless, bipyramidal crystals of orthorhombic symmetry.
Gismondine was named for Italian mineralogist Carlo Giuseppe Gismondi (1762–1824). It has been found in Iceland, Ireland, and Italy.
==References== *[http://www.britannica.com/eb/article-9036927/gismondine Encyclopædia Britannica online entry] *[http://webmineral.com/data/Gismondine.shtml Gismondine data at webmineral.com]
==External links== *[http://helios.princeton.edu/zeomics/cgi-bin/view_structure.pl?src=iza&id=GIS Structure type GIS]
Category:Zeolite group Category:Monoclinic minerals Category:Minerals in space group 14
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