AskDefine | Define pyrolusite

Dictionary Definition

pyrolusite n : a mineral consisting of manganese dioxide; an important source of manganese

User Contributed Dictionary

English

Noun

pyrolusite
  1. A dark coloured mineral, consisting of manganese dioxide (MnO2), that is an important ore of manganese.

Extensive Definition

Pyrolusite is a mineral consisting essentially of manganese dioxide (MnO2) and is important as an ore of manganese. It is a soft, black, amorphous appearing mineral, often with a granular, fibrous or columnar structure, sometimes forming reniform crusts. It has a metallic luster, a black or bluish-black streak, and readily soils the fingers. The specific gravity is about 4.8.
Pyrolusite and rhodochrosite are among the most common manganese minerals. The metal is obtained by reduction of the oxide with sodium, magnesium, aluminium, or by electrolysis. Pyrolusite is extensively used for the manufacture of spiegeleisen and ferromanganese and of various alloys such as manganese-bronze. As an oxidizing agent it is used in the preparation of chlorine and disinfectants (permanganates) and for decolorizing glass. When mixed with molten glass it oxidizes the ferrous iron to ferric iron, and so discharges the green and brown tints. As a coloring material, it is used in calico printing and dyeing; for imparting violet, amber and black colors to glass, pottery and bricks; and in the manufacture of green and violet paints.

Variations in crystal habit

pyrolusite in Bosnian: Piroluzit
pyrolusite in German: Pyrolusit
pyrolusite in Spanish: Pirolusita
pyrolusite in Hebrew: פירולוזיט
pyrolusite in Hungarian: Piroluzit
pyrolusite in Dutch: Pyrolusiet
pyrolusite in Japanese: 軟マンガン鉱
pyrolusite in Polish: Piroluzyt
pyrolusite in Portuguese: Pirolusita
pyrolusite in Romanian: Piroluzit
pyrolusite in Russian: Пиролюзит
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