penninite

noun

pen·​ni·​nite

ˈpenəˌnīt

variants or less commonly pennine

ˈpenə̇n,

-ˌnīn

plural -s

: a mineral approximately (Mg,Fe,Al)₆(Si,Al)₄O₁₁(OH)₈ of the chlorite group consisting of a basic aluminosilicate of magnesium, iron, and aluminum, that is monoclinic and is commonly emerald or olive green (hardness 2.–2.5, specific gravity 2.6–2.85)

Word History

Etymology

penninite from German pennin (from Pennine Alps) + English -ite; pennine from German pennin

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