noun
pyrolusite
A manganese dioxide mineral; the most important ore of manganese. Technical term used in geology and mineralogy.
軟マンガン鉱はマンガンの主要な鉱石鉱物である。
Pyrolusite is the primary ore mineral of manganese.
Compound of 軟 (nan, 'soft') + マンガン (mangan, 'manganese') + 鉱 (kō, 'ore'). The name likely refers to the mineral's relatively low hardness compared to other manganese ores.