Stilbite
Stilbite is the name of a series of tectosilicate minerals of the zeolite group. Prior to 1997, stilbite 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:
Stilbite-Ca, by far the more common of the two, is a hydrous calcium sodium and aluminium silicate, NaCa4(Si27Al9)O72·28(H2O). In the case of stilbite-Na, sodium dominates over calcium. The species are visually indistinguishable, and the series name stilbite is still used whenever testing has not been performed.
History
At one time heulandite and stilbite were considered to be identical minerals. After they were found to be two separate species, in 1818, the name desmine ("a bundle") was proposed for stilbite, and this name is still employed in Germany. The English name "stilbite" is from the Greek stilbein = to shine, because of the pearly luster of the {010} faces.
Chemistry and related species
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