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.
For more information go to http://en.wikipedia.org/wiki/Pyrolusite
Item # PYRO02146641
Pyrolusite from Alberta, Michigan
Nice metallic Pyrolusite acicular fan pattern crystals on banded Chert with Goethite. This specimen is from the Taylor Mine near Alberta, Baraga County, Michigan. Alberta was once owned by the Ford Company. The Alberta sawmill supplied the wooden sides of Henry Ford’s Model T's.
weighs 7.6oz or 0.48lb (217g) and measures 3.5 x 2.2 x 1 inch (9 x 5.8 x 2.7cm)