synadelphite
noun
syn·a·del·phite
| \ ˌsinəˈdelˌfīt\
plural -s
Definition of synadelphite
: 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)
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