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neptunite

noun
nep·​tun·​ite | \-ˌnīt\
plural -s

Definition of neptunite 

: a mineral (Na,K)2(Fe,Mn)TiSi4O12 consisting of a silicate of iron, manganese, potassium, sodium, and titanium

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History and Etymology for neptunite

Swedish neptunit, from Latin Neptunus Neptune + Swedish -it -ite

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