- a white or transparent, colorless mineral of the zeolite family, hydrous calcium aluminum silicate, CaAl2Si7O18⋅6H2O, occurring in basic volcanic rocks in the form of crystals with a pearly luster.
- a white, grey, red, or brown zeolite mineral that consists essentially of hydrated calcium aluminium silicate in the form of elongated tabular crystals. Formula: CaAl 2 Si 7 O 18 .6H 2 O
