Gismondine is a mineral with the chemical formula CaAl2Si2O8·4(H2O).

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.

This article about a specific silicate mineral is a stub.