Barrerite

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Barrerite
Barrerite-27538.jpg
Barrerite from Kuiu Island, Alaska, USA.
General
Category Zeolite
Formula
(repeating unit)
(Na,K,Ca)2Al2Si7O18·6(H2O)
Strunz classification 9.GE.15
Crystal system Orthorhombic
Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space group Amma
Identification
Color White, pink
Cleavage Perfect
Mohs scale hardness 3 - 4
Luster Vitreous-glassy
Streak White
Diaphaneity Transparent to translucent
Specific gravity 2.13
Optical properties Biaxial (-)
Refractive index nα = 1.479 nβ = 1.485 nγ = 1.489
References [1][2][3]

Barrerite is a tectosilicate mineral and a member of the zeolite family. It is one of the rarer zeolites. It was named for Richard Barrer, a New Zealand-born chemist.[3]

Barrerite crystal are white to pinkish, with a vitreous-glassy luster. The crystal system is orthorhombic and is flat and tabular in appearance. It has a Mohs hardness of 3 to 4 and its cleavage is perfect. Barrerite has a white streak and a density of 2.13.

It was first described in 1974 for an occurrence in Sardinia at Sant' Efisio Tower on Cape Pula in Cagliari Province.[3] It has also been reported from Rocky Pass, Kuiu Island, Alaska, and a few other localities.

References[edit]