A steel-gray to black mineral, MnO(OH), present North America and European countries; manganese oxide.
a dark gray mineral of manganese, MnO(OH), discovered throughout the united states and Europe
among the oxides of manganese; -- called in addition gray manganese ore. It happens in brilliant steel-gray or iron-black crystals, in addition massive.
A compound of manganese dioxide with a metallic oxide; so-called as though produced by the hypothetical manganous acid.
A hydrated oxid of manganese occurring in orthorhombic crystals of a steel-gray or iron-black shade and brilliant luster, additionally in masses having a columnar structure. It is modified, by reduced liquid, to pyrolusite. Also called grey manganese ore.
A substance which can be seen as a compound of manganese dioxid aided by the monoxid of an even more standard or electropositive steel.
a black mineral consisting of basic manganese oxide; a source of manganese