| pyrolusite | <chemical> Manganese dioxide, a mineral of an iron-black or dark steel-gray colour 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). Origin: Pyro- + Gr. To loose, or a loosing. Source: Websters Dictionary (01 Mar 1998) |
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