| heulandite | (n) a group of minerals of the zeolite family consisting of a hydrous aluminum silicate of sodium and calcium |
| Heulandite | n. [ After Heuland, an English mineralogist. ] (Min.) 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. [ 1913 Webster ] |