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glaucophane
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Basalt sample returned by Apollo 15, from near a long sinous lunar valley called Hadley Rille. Measured at 3.3 years old.
(Bed) Rocks and (Flint) Stones
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glaucophane
glaucophane

glaucophane

mineral
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glaucophane, common amphibole mineral, a sodium, magnesium, and aluminum silicate that occurs only in crystalline schists formed from sodium-rich rocks by low-grade metamorphism characteristic of subduction zones. Glaucophane typically occurs in folded rocks associated with blueschists. Both ferrous and ferric iron are replaced by magnesium and aluminum in the crystal structure to form riebeckite. For chemical formula and detailed physical properties, see amphibole (table).

This article was most recently revised and updated by Amy Tikkanen.