Heulandite has 2 different meanings across 1 category:
Noun
a group of minerals of the zeolite family consisting of a hydrous aluminum silicate of sodium and calcium
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.