Heulandite/Mordenite Crystal Mineral Specimen
HISTORY, NAME, LOCALITIES: Heulandite, pronounced HEW-lan-dite, was identified as a mineral species in 1818 and named for the 19th-century British mineral dealer and collector John Henry Heuland. The name “Heulandite-(Ca)” was assigned in the 1990s when the zeolite-mineral classification system was revised. The “-(Ca)” suffix designates it as the calcium-rich member of the heulandite group. Notable collecting localities are in India, Iceland, Denmark, England, Norway, Canada, and the United States (Idaho, Colorado, New Jersey, Oregon).
MINERALOGY, PROPERTIES, OCCURRENCE: Heulandite-(Ca) [hydrous calcium sodium potassium aluminosilicate, (Ca0.5,Na,K)(Al9Si27O72)·~24H2O] crystallizes in the monoclinic system, usually as well-formed, coffin-shaped crystals; single tabular crystals; radiating aggregates of parallel crystals; and in foliated, granular, and globular forms. It is translucent to transparent and most often white, but also exhibits pale shades of green, peach, and orange. Heulandite-(Ca) has a Mohs hardness of 3.5-4.0, perfect cleavage in one direction, a vitreous-to-pearly luster, and a specific gravity of 2.1-2.3. It is a zeolite mineral that occurs mainly in amygdaloidal cavities in basalt.
METAPHYSICAL PROPERTIES, LORE, USES: Because of its softness and a low index of refraction, heulandite-(Ca) is not used as a gemstone. Heulandite-(Ca) is mined along with other zeolite minerals for absorption, filtration, fertilizer-additive, and ion-exchange uses. Metaphysical practitioners believe that heulandite-(Ca) and other heulandite-group members enhance awareness and aid in recovery from the emotional trauma of loss.
COLLECTORS’ INFORMATION: Heulandite-(Ca) has long been valued by mineral collectors as both single and composite specimens, the latter in association with other zeolite minerals.