Heulandite

noun

1. A white, red, or yellow zeolite mineral, CaO·Al2O3·6SiO2·5H2O.
2. A mineral belonging to the zeolite group.
3. A mineral of the Zeolite family, often occurring in amygdaloid, in foliated masses, and also in monoclinic crystals with pearly luster on the cleavage face. It is a hydrous silicate of alumina and lime.
4. A common mineral of the zeolite group with monoclinic crystals, the most usual form being heulandite-Ca (Ca,Na)2-3Al3(Al,Si)2Si13O36·12H2O.
5. a group of minerals of the zeolite family consisting of a hydrous aluminum silicate of sodium and calcium