Ferrierite-Na Locality: Monte Lake, Kamloops Mining Division, British Columbia , Canada ( Locality at mindat.org ) Size: miniature, 3.2 x 2.6 x 2.5 cm Ferrierite-Mg A very attractive "pocket" specimen of ferrierite from this type locality. Ferrierite is a rare zeolite species Named for Walter Frederick Ferrier (1865-1950), Canadian geologist and mining engineer (MINDAT). Ex. John White Collection. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Ferrierite-Na
The ferrierite group of zeolite minerals (the FER structure) consists of four very similar species: ferrierite-Mg, ferrierite-Na, ferrierite-NH4 and ferrierite-K, based on the dominant cation in the A location. ferrierite-Mg and ferrierite-K are orthorhombic minerals and ferrierite-Na is monoclinic with highly variable cationic composition (Na,K)2Mg(Si,Al)18O36(OH)·9H2O. Calcium and other ions are often also present. They are found in vitreous to pearly, often radiating, spherical aggregates of thin blade-shaped transparent to translucent crystals.
Intro adapted from Wikipedia (CC BY-SA).
Ferrierite-Na is an IMA-recognized mineral species in the silicate class, with the chemical formula (Na,K)₅(Si₃₁Al₅)O₇₂·18H₂O.
It crystallizes in the orthorhombic crystal system (space group Immm). It is a member of the Ferrierite structural group.
Key properties: Mohs hardness 3–3.5; specific gravity 2.136; White streak; Vitreous to pearly luster; optically biaxial.
IMA symbol Frr-Na, IMA status: approved, named in 1997.
Found in seams and vesicles in deeply weathered basalts, flow breccias, and andesites; in tuffaceous sediments.
It is found associated with Zeolites, plagioclase, \hypersthene, " augite, montmorillonite, \chalcedony, " calcite.
The name refers to Dr. Walter Frederick Ferrier (1865–1950), geologist and mining engineer with the Canadian Geological Survey.