py·ro·lu·site /ˌpaɪroˈluˌsaɪt/
  軟錳礦; 軟鐵礦
  Pyr·o·lu·site n.  Min. Manganese dioxide, a mineral of an iron-black or dark steel-gray color and metallic luster, usually soft.  Pyrolusite parts with its oxygen at a red heat, and is extensively used in discharging the brown and green tints of glass (whence its name).
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  pyrolusite
       n : a mineral consisting of manganese dioxide; an important
           source of manganese