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osumilite

n. A hexagonal mineral with the chemical formula (K,Na)(Mg,Fe+2)2(Al,Fe)3(Si,Al)12O30·H2O.

Wikipedia
Osumilite

Osumilite a very rare potassium-sodium-iron-magnesium-aluminium silicate mineral. Osumilite is part of the milarite group (also known as the milarite-osumilite group) of cyclosilicates.