This MedLibrary.org supplementary page on Pyrolusite is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:
Related Sponsors
| Pyrolusite | |
|---|---|
 Pyrolusite Mineral with Dendrite (height of sample ~9 cm)
|
|
| General | |
| Category | Mineral |
| Chemical formula | manganese dioxide, MnO2 |
| Identification | |
| Color | Darkish, black to lighter grey, somethimes bluish |
| Crystal habit | Granular to massive: botryoidal and dendritic |
| Crystal system | Tetragonal |
| Cleavage | Perfect on 100 and 011 |
| Fracture | Rough |
| Mohs Scale hardness | 2–2.5 |
| Luster | Metallic |
| Refractive index | Opaque |
| Pleochroism | None |
| Streak | Same as color |
| Specific gravity | 4.73–4.86 |
| Major varieties | |
| Polianite | Massive crystals of the very pure form |
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
This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain.
 |
This article about a specific mineral or mineraloid is a stub. You can help Wikipedia by expanding it. |
|
||||||||||||||||||||||||||||
Wikipedia content modification information:
- This page was last modified on 29 September 2008, at 21:47.
Wikipedia Authorship and Review
Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.
Wikipedia Usage Guidelines
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Pyrolusite".
The URL for this specific entry is:
All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.