Clinoptilolite-Na

Clinoptilolite-Na Locality: Rodalquilar, Níjar, Almería, Andalusia, Spain Picture width 2.5 mm. Collection and photograph Christian Rewitzer — Photo: Christian Rewitzer · CC BY-SA 3.0

Clinoptilolite-Na

Clinoptilolite-Na is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₆(Si₃₀Al₆)O₇₂·20H₂O.

It crystallizes in the monoclinic crystal system (space group C2/m). It is a member of the Heulandite structural group.

Key properties: Mohs hardness 3.5–4; specific gravity 2.16; Vitreous luster; optically biaxial.

IMA symbol Cpt-Na, IMA status: approved, named in 1969.

Formed by devitrification of volcanic glass, and in cavities in rhyolites and andesites.

It is found associated with Zeolites, montmorillonite, hectorite, thenardite, halite, gaylussite, celadonite, quartz, \opal, " calcite.

The name refers to its inclined optics and relation to ptilolite [mordenite].