Fewrrierite-(Mg) Kamloops Lake British Columbia, Canada — Photo: Beancounter603 · CC BY-SA 3.0
Ferrierite-Mg
Also known as: Ferrierite.
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-Mg is an IMA-recognized mineral species in the silicate class, with the chemical formula [Mg₂(K,Na)₂Ca₀.₅](Si₂₉Al₇)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; typically white or colorless or orange; white streak; vitreous luster.
IMA symbol Frr-Mg, IMA status: approved, named in 1918.
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