Pyrolusite

Pyrolusite is a common manganese mineral, manganese dioxide, (MnO2) that constitutes an important ore. Its name is from the Greek for fire and to wash (in reference to its use as a way to remove tints from glass). It is always formed under highly oxidizing conditions, it forms light-gray to black, metallic, moderately heavy coatings, crusts, or fibers that are alteration products of other manganese ores, bogs, lakes, or deposits left by circulating waters. Pyrolusite is mined in Germany, Brazil, India, the United States, Cuba, Morocco, and South Africa. Pyrolusite is used in the manufacture of steel, manganese bronze, battery dry cells and as a decolorizing agent in glass.

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