Barrerite from Kuiu Island, Alaska, USA.
|Crystal system||Orthorhombic Dipyramidal H-M Symbol (2/m 2/m 2/m)|
|Mohs scale hardness||3 - 4|
|Diaphaneity||Transparent to translucent|
|Optical properties||Biaxial (-)|
|Refractive index||nα = 1.479 nβ = 1.485 nγ = 1.489|
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. It has also been reported from Rocky Pass, Kuiu Island, Alaska, and a few other localities.
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