synadelphite

noun

syn·​a·​del·​phite

ˌsinəˈdelˌfīt

plural -s

: a mineral (Mn,Mg,Ca,Pb)(AsO₄)(OH)₅ composed of a basic arsenate of manganese often with other elements (such as magnesium, calcium, lead) and occurring in black prismatic crystals and grains (hardness 4.5, specific gravity 3.5)

Word History

Etymology

German synadelphit, from Greek synadelphos one that has a brother or sister (from syn- + adelphos brother) + German -it -ite

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