01 n. One of the oxides of manganese; -- called also gray manganese ore. It occurs in brilliant steel-gray or iron-black crystals, also massive.
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1.
One of the oxides of manganese; -- called also gray manganese ore. It occurs in brilliant steel-gray or iron-black crystals, also massive.(Min.) Also: gray manganese ore
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2.
A compound of manganese dioxide with a metallic oxide; so called as though derived from the hypothetical manganous acid.(Chem.)