One of the oxides of manganese; -- called also gray manganese ore. It occurs in brilliant steel-gray or iron-black crystals, also massive.
A compound of manganese dioxide with a metallic oxide; so called as though derived from the hypothetical manganous acid.
a black mineral consisting of basic manganese oxide; a source of manganese
Steel-gray or iron-black crystals composed of manganese oxide. Used as a source of manganese.
a hydrated oxide of manganese, occurring in steel-gray or iron-black masses or crystals. [AHDOS
Manganite is a mineral. Its composition is manganese oxide-hydroxide, MnO(OH), crystallizing in the orthorhombic system and isomorphous with diaspore and goethite. Crystals are prismatic and deeply striated parallel to their length; they are often grouped together in bundles.