allactite
noun
al·lac·tite
əˈlakˌtīt
plural -s
: a mineral consisting of a brownish red basic manganese arsenate Mn7(AsO4)2(OH)8
Word History
Etymology
International Scientific Vocabulary allact- (irregular from Greek allag-, stem of allassein to change, from allos other) + -ite; originally formed as Swedish allaktit
First Known Use
1884, in the meaning defined above