gismondine

{{Short description|Zeolite mineral}}

{{Infobox mineral

| name = Gismondine

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| image = Gismondina Calatrava.jpg

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| caption = Gismondine, Campo de Calatrava, Ciudad Real, Spain

| category = Tectosilicate minerals, zeolite group

| formula = CaAl₂Si₂O₈·4(H₂O)

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| dana = 77.1.3.1

| system = Monoclinic

| class = Prismatic (2/m)
(same H-M symbol)

| symmetry = P2₁/n

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Gismondine is a mineral with the chemical formula CaAl₂Si₂O₈·4(H₂O). It is a zeolite or hydrated alumino-silicate. 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.