'Pyrolusite' definitions:
Definition of 'pyrolusite'
From: WordNet
noun
A mineral consisting of manganese dioxide; an important source of manganese
Definition of 'Pyrolusite'
From: GCIDE
- Pyrolusite \Pyr`o*lu"site\, n. [Pyro- + Gr. ? to loose, or ? a loosing.] (Min.) Manganese dioxide, a mineral of an iron-black or dark steel-gray color and metallic luster, usually soft. Pyrolusite parts with its oxygen at a red heat, and is extensively used in discharging the brown and green tints of glass (whence its name). [1913 Webster]