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Formula: (Na,K)5(Si31Al5)O72.18H2O
Tectosilicate (framework silicate), ferrierite subgroup,
zeolite group
Crystal System: Monoclinic
Specific gravity: 2.136 measured, 2.11 calculated
Hardness: 3 to 3½
Streak: White
Colour: White, colourless, pinkish, orange to red
Environments
Ferrierite-Na occurs in seams and vesicles in deeply weathered
basalts, flow breccias
and andesites, and also in
tuffaceous sediments. Associated minerals include
zeolites, plagioclase,
hypersthene,
augite, montmorillonite,
chalcedony and calcite
(HOM, as ferrierite).
Localities
At Cornell Road, Agoura Hills, Los Angeles County, California, USA,
clinoptilolite and ferrierite-Na occur in a
breccia exposed in a quarry along Cornell Road, 6 miles southwest of
Agoura. The host rock is a brecciated
porphyritic
andesite, composed of microphenocrysts of
plagioclase and hypersthene
set in a glass-rich groundmass.
Cavities in the breccia are lined with a
montmorillonitic clay
covered by chalcedony. Some cavities have
calcite also covered by
chalcedony. The
clinoptilolite occurs as clusters of platy crystals and is partially
intergrown with tufts of very small (0.01 mm thick), soft, white ferrierite-Na needles
(AM 54.887-895 as ferrierite).
Type Locality:ⓘ Altoona-Pillar Rock Road roadcuts, Altoona, Wahkiakum County, Washington, USA
Ferrierite-Na from the
Altoona-Pillar Rock Road roadcuts - Image
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