Wiktionary
alleghanyite
n. (context mineral English) A monoclinic-prismatic mineral containing hydrogen, manganese, oxygen, and silicon.
Wikipedia
Alleghanyite
Alleghanyite is a moderately rare humite mineral with formula Mn(SiO)(OH), belonging to the nesosilicates class. In general its occurrences are related with metamorphic (metamorphosed) manganese deposits. The mineral is named after Alleghany County, North Carolina, US.