variants or less commonly pennine
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


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

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Cite this Entry

“Penninite.” Dictionary, Merriam-Webster, Accessed 26 Jan. 2023.

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