Psilomelane
[sai'lɔmilein]
Definition
(noun.) a mineral consisting of hydrated basic oxide of manganese and barium; a source of manganese.
Edited by Benson--From WordNet
Definition
(n.) A hydrous oxide of manganese, occurring in smooth, botryoidal forms, and massive, and having an iron-black or steel-gray color.
Typed by Eliza