Heulandite is distinguished from stilbite by its crystals and perfect solubility; from apopholite by form of crystals.
"Scientific American Supplement, No. 344, August 5, 1882" by Various
Isomorphous with heulandite is the strontium and barium zeolite brewsterite, named after Sir David Brewster.
"Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4" by Various