Stilbite-Ca Locality: Jalgaon District, Maharashtra, India (Locality at mindat.org) Size: cabinet, 14.7 x 7.5 x 6.6 cm Stilbite A bed of white chalcedony acts a — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Stilbite-Ca
Also known as: Stilbite, Desmine.
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 Stilbite-Na, sometimes also called stiblite 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.
Intro adapted from Wikipedia (CC BY-SA).
Stilbite-Ca is an IMA-recognized mineral species in the silicate class, with the chemical formula NaCa₄(Si₂₇Al₉)O₇₂·28H₂O.
It crystallizes in the monoclinic crystal system (space group Fmmm). It is a member of the Stilbite structural group.
Key properties: Mohs hardness 3.5–4; specific gravity 2.19; typically white or pink or orange or brown or yellow or red; White streak; Vitreous, pearly on cleavage luster; optically biaxial.
IMA symbol Stb-Ca, IMA status: approved, named in 1801.
A low-temperature hydrothermal mineral, in amygdules and cavities in basalts, andesites, and various metamorphic rocks. Formed in hot springs deposits, and as a cementing agent in some sandstones and conglomerates.
It is found associated with Zeolites, prehnite, calcite, quartz.
Its name comes from the Greek for luster, in reference to its pearly luster.
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