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Formula: NaCa4(Si27Al9)O72
.28H2O
Tectosilicate (framework silicate), stilbite subgroup of the
zeolite group
Crystal System: Monoclinic (pseudo orthorhombic)
Specific gravity: 2.19 measured, 2.23 calculated
Hardness: 3½ to 4
Streak: White
Colour: White, red, yellow, brown, cream
Luminescence: May fluoresce pale-yellow or blue-white in short wave UV
Solubility: Moderately soluble in hydrochloric acid
Environments:
Metamorphic environments
Basaltic cavities
Stilbite-Ca is a low-temperature hydrothermal mineral occurring in amygdaloidal cavities in
basalts, andesites, and
various metamorphic rocks. Formed in hot springs deposits, and as a cementing agent in some
sandstones and
conglomerates. Associated minerals include
zeolites, prehnite,
calcite and quartz
(HOM).
Localities
At Wasson Bluff, Two Islands, Cumberland County, Nova Scotia, Canada, exellent fans of orange stilbite
have been found
(Mindat photo).
Stilbite-(Ca) from Wasson Bluff - Image
At the Houdaille Quarry, Springfield, Springfield Township, Union County, New Jersey, USA, stilbite-Ca has been
found with heulandite
(Mindat photo).
Stilbite-Ca from the Houdaille Quarry -
Image
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