tilasite

noun

til·​as·​ite

ˈtiləˌsīt

plural -s

: a mineral CaMg(AsO₄)F consisting of a magnesium calcium arsenate and fluoride and occurring in violet-gray granular masses (specific gravity 3.3)

Word History

Etymology

Swedish tilasit, from Daniel Tilas †1772 Swedish mining engineer + Swedish -it -ite

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