glaucophane

American  

[glaw-kuh-feyn] / ˈglɔ kəˌfeɪn /

noun

1. a sodium-rich monoclinic mineral of the amphibole family, usually metamorphic.

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glaucophane Scientific  

/ glou′kə-fān′ /

1. A blue to grayish-blue or bluish-black monoclinic mineral of the amphibole group. Glaucophane occurs as fibrous prisms in schists (especially blueschists) formed by the regional metamorphism of sodium-rich rocks. Chemical formula: Na ₂ (Mg,Fe) ₃ Al ₂ Si ₈ O ₂₂ (OH) ₂ .

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Etymology

Origin of glaucophane

First recorded in 1840–50; glauco- + -phane ( def. )