Man·ga·nese n.  Chem. An element obtained by reduction of its oxide, as a hard, grayish white metal, fusible with difficulty (melting point 1244° C), but easily oxidized.  Its ores occur abundantly in nature as the minerals pyrolusite, manganite, etc.  Symbol Mn.  Atomic number 25; Atomic weight 54.938 [C=12.011].
 Note: ☞ An alloy of manganese with iron (called ferromanganese) is used to increase the density and hardness of steel.
 Black oxide of manganese, Manganese dioxide or Manganese peroxide, or Black manganese Chem., a heavy black powder MnO2, occurring native as the mineral pyrolusite, and valuable as a strong oxidizer; -- called also familiarly manganese. It colors glass violet, and is used as a decolorizer to remove the green tint of impure glass.

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