millisite

noun

mil·​lis·​ite

ˈmilə̇ˌsīt

plural -s

: a mineral (Na,K)CaAl₆(PO₄)₄(OH)₉.3H₂O consisting of a basic hydrous phosphate of sodium, potassium, calcium, and aluminum

Word History

Etymology

F. T. Millis, 20th century American mineral collector + English -ite

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