Heulandite Subgroup from selected localities.
Faroe Islands | |
| Betz, V. (1981): Famous mineral localities: Zeolites from Iceland and the Faeroes. Mineralogical Record 12 (1), 5-26.; Tschernich, R. W. (1992): Zeolites of the world. Geoscience Press, Phoenix, Arizona.(p.459) |
| Zeolite collection of Volker Betz; Sussex Mineral and Lapidary Society (SMLS) Journal 234 Nov/Dec 2011 |