Heulandite (Paperback)

High Quality Content by WIKIPEDIA articles! Heulandite is the name of a series of tecto-silicate minerals of the zeolite group. Prior to 1997, heulandite was recognized as a mineral species, but a reclassification in 1997 by the International Mineralogical Association changed it to a series name, with the mineral species being named heulandite-Ca, heulandite-Na, heulandite-K, and heulandite-Sr. Heulandite-Ca, the most common of these, is a hydrous hydrous calcium and aluminium silicate, (Ca,Na)2-3Al3(Al,Si)2Si13O3612H2O. Small amounts of sodium and potassium are usually present replacing part of the calcium. Strontium replaces calcium in the heulandite-Sr variety. The appropriate species name depends on the dominant element. The species are visually indistinguishable, and the series name heulandite is still used whenever testing has not been performed.