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Pyrolusite

Pyrolusite

Pyrolusite mineral with dendrite (height of sample ~ 9 cm).

General

Category Oxide minerals

Formula

(repeating unit)

MnO2

Strunz classification 04.DB.05

Identification

Color Darkish, black to lighter grey, somethimes bluish

Crystal habit Granular to massive: botryoidal and dendritic. Crystals rare

Crystal system Tetragonal

Twinning {031}, {032} may be polysynthetic

Cleavage Perfect on 110

Fracture Brittle

Mohs scale hardness 66.5, 2 when massive

Luster Metallic, dull to earthy

Streak Black to bluish-black

Specific gravity 4.45.06

Refractive index Opaque

References [1][2][3]

Major varieties

Polianite pseudomorphic after manganite[4]

Pyrolusite is a mineral consisting essentially of manganese dioxide (MnO2) and is important as an ore of

manganese. It is a 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. Its name is from the Greek for fire and to wash, in reference to its use as a

way to remove tints from glass.[3]

http://en.wikipedia.org/w/index.php?title=Specific_gravityhttp://en.wikipedia.org/w/index.php?title=Lustre_%28mineralogy%29http://en.wikipedia.org/w/index.php?title=Orehttp://en.wikipedia.org/w/index.php?title=Oxygenhttp://en.wikipedia.org/w/index.php?title=Manganesehttp://en.wikipedia.org/w/index.php?title=Manganese_dioxidehttp://en.wikipedia.org/w/index.php?title=Mineralhttp://en.wikipedia.org/w/index.php?title=Manganitehttp://en.wikipedia.org/w/index.php?title=Refractive_indexhttp://en.wikipedia.org/w/index.php?title=Specific_gravityhttp://en.wikipedia.org/w/index.php?title=Streak_%28mineralogy%29http://en.wikipedia.org/w/index.php?title=Lustre_%28mineralogy%29http://en.wikipedia.org/w/index.php?title=Mohs_scale_of_mineral_hardnesshttp://en.wikipedia.org/w/index.php?title=Fracture_%28mineralogy%29http://en.wikipedia.org/w/index.php?title=Cleavage_%28crystal%29http://en.wikipedia.org/w/index.php?title=Crystal_twinninghttp://en.wikipedia.org/w/index.php?title=Tetragonalhttp://en.wikipedia.org/w/index.php?title=Crystal_systemhttp://en.wikipedia.org/w/index.php?title=Crystal_habithttp://en.wikipedia.org/w/index.php?title=Strunz_classificationhttp://en.wikipedia.org/w/index.php?title=Chemical_formulahttp://en.wikipedia.org/w/index.php?title=Oxide_mineralshttp://en.wikipedia.org/w/index.php?title=File:Pyrolusite_Mineral_with_Dendrite_Macro_Digon3.jpg

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Occurrence

Pyrolusite and romanechite are among the most common manganese minerals. Pyrolusite occurs associated with

manganite, hollandite, hausmannite, braunite, chalcophanite, goethite and hematite under oxidizing conditions in

hydrothermal deposits. It also occurs in bogs and often results from alteration of manganite.[3]

Use

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; indeed, chlorine gas itself was first

described by Karl Scheele in 1774 from the reaction products of pyrolusite and hydrochloric acid. Natural pyrolusite

has been used in batteries, but high-quality batteries requires synthetic products. Pyrolusite is also used to prepare

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 (making it classically useful to glassmakers as a

decolorizer). 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

Botryoidal Dendritic

Acicular radiating crystal structure of pyrolusite

http://en.wiktionary.org/wiki/acicularhttp://en.wikipedia.org/w/index.php?title=File%3ARutile-unit-cell-3D-balls.pnghttp://en.wikipedia.org/w/index.php?title=File%3APyrolusite_radiating.jpghttp://en.wiktionary.org/wiki/acicularhttp://en.wikipedia.org/w/index.php?title=File%3APyrolusite_dendritic.jpghttp://en.wikipedia.org/w/index.php?title=Dendrite_%28crystal%29http://en.wikipedia.org/w/index.php?title=File%3APyrolusite_botryoidal.jpghttp://en.wikipedia.org/w/index.php?title=Botryoidalhttp://en.wikipedia.org/w/index.php?title=Amber_%28color%29http://en.wikipedia.org/w/index.php?title=Ironhttp://en.wikipedia.org/w/index.php?title=Permanganatehttp://en.wikipedia.org/w/index.php?title=Manganese_dioxidehttp://en.wikipedia.org/w/index.php?title=Hydrochloric_acidhttp://en.wikipedia.org/w/index.php?title=Karl_Scheelehttp://en.wikipedia.org/w/index.php?title=Chlorinehttp://en.wikipedia.org/w/index.php?title=Bronzehttp://en.wikipedia.org/w/index.php?title=Ferromanganesehttp://en.wikipedia.org/w/index.php?title=Spiegeleisenhttp://en.wikipedia.org/w/index.php?title=Electrolysishttp://en.wikipedia.org/w/index.php?title=Aluminiumhttp://en.wikipedia.org/w/index.php?title=Magnesiumhttp://en.wikipedia.org/w/index.php?title=Sodiumhttp://en.wikipedia.org/w/index.php?title=Boghttp://en.wikipedia.org/w/index.php?title=Hydrothermalhttp://en.wikipedia.org/w/index.php?title=Redoxhttp://en.wikipedia.org/w/index.php?title=Hematitehttp://en.wikipedia.org/w/index.php?title=Goethitehttp://en.wikipedia.org/w/index.php?title=Chalcophanitehttp://en.wikipedia.org/w/index.php?title=Braunitehttp://en.wikipedia.org/w/index.php?title=Hausmannitehttp://en.wikipedia.org/w/index.php?title=Hollanditehttp://en.wikipedia.org/w/index.php?title=Manganitehttp://en.wikipedia.org/w/index.php?title=Romanechite

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References

[1] http:/ /webmineral.com/data/Pyrolusite.shtml Webmineral data

[2] http:/ /www.mindat. org/min-3318. html Mindat

[3] http:/ /rruff.geo. arizona.edu/doclib/hom/pyrolusite. pdf Handbook of Mineralogy

[4] http:/ /www.mindat. org/min-6101. html Mindat polianite

This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911).

Encyclopdia Britannica (11th ed.). Cambridge University Press.

http://en.wikipedia.org/w/index.php?title=Encyclop%C3%A6dia_Britannica_Eleventh_Editionhttp://en.wikipedia.org/w/index.php?title=Public_domainhttp://www.mindat.org/min-6101.htmlhttp://rruff.geo.arizona.edu/doclib/hom/pyrolusite.pdfhttp://www.mindat.org/min-3318.htmlhttp://webmineral.com/data/Pyrolusite.shtml

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Article Sources and Contributors 4

Article Sources and ContributorsPyrolusite Source: http://en.wikipedia.org/w/index.php?oldid=525217336 Contributors: Aramgutang, Aussie Alchemist, Avicennasis, Avihu, Berkut, Bons, Br77rino, Chris 73, Chris.urs-o,

D6, DanielCD, Digon3, DuncanHill, Eastlaw, Fiveless, Flowerparty, Gil Gamesh, Hyperdeath, Jaraalbe, Ligulem, Magnus Manske, Materialscientist, Msh210, Nux, Rhanyeia, Sbharris,

Shinkolobwe, Stan J Klimas, Stan Shebs, Vsmith, 18 anonymous edits

Image Sources, Licenses and ContributorsFile:Pyrolusite Mineral with Dendrite Macro Digon3.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Pyrolusite_Mineral_with_Dendrite_Macro_Digon3.jpgLicense: unknown

Contributors: Jonathan Zander (Digon3)"

Image:Pyrolusite botryoidal.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Pyrolusite_botryoidal.jpgLicense: Public domain Contributors: Aram Dulyan (User:Aramgutang)

Image:Pyrolusite_dendritic.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Pyrolusite_dendritic.jpgLicense: Public domain Contributors: Aram Dulyan (User:Aramgutang)

Image:Pyrolusite_radiating.jpg Source: http://en.wikipedia.org/w/index.php?title=File:Pyrolusite_radiating.jpg License: Public domain Contributors: Aram Dulyan (User:Aramgutang)

Image:Rutile-unit-cell-3D-balls.png Source: http://en.wikipedia.org/w/index.php?title=File:Rutile-unit-cell-3D-balls.pngLicense: Public Domain Contributors: Ben Mills

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