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Pyrolusite

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Formula:
MnO2
Colour:
Black or very dark grey.
Lustre:
Metallic, Dull, Earthy
Hardness:
2 - 6½
Specific Gravity:
5.04 - 5.08
Crystal System:
Tetragonal
Member of:
Name:
Named in 1827 from the Greek for "fire" and "to wash," because it was used to remove brown and green tints in the making of glass.
Rutile Group.

Usually found as matte-black powdery to fibrous crusts, sometimes in botryoidal aggregates or columnar, more rarely as druzes of small prismatic to tabular, dark grey metallic crystals.
May be confused with some manganese oxides such as todorokite (fibrous variants) and manganite (tabular crystals).

NOTE: No valid pyrolusite dendrites are known. Supposed specimens of pyrolusite in dendritic form turn out to be other Mn-oxide species (e.g., minerals of the cryptomelane group, birnessite, nsutite, todorokite, etc.) upon being examined in the proper laboratory setting for characterizing these difficult to identify minerals; see Potter and Rossman (1979).


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Classification of PyrolusiteHide

Approved, 'Grandfathered' (first described prior to 1959)
4.DB.05

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
B : With medium-sized cations; chains of edge-sharing octahedra
Dana 7th ed.:
4.4.1.4
4.4.1.4

4 : SIMPLE OXIDES
4 : AX2
7.18.3

7 : Oxides and Hydroxides
18 : Oxides of Mn

Pronounciation of PyrolusiteHide

Pronounciation:
PlayRecorded byCountry
Jolyon & Katya RalphUnited Kingdom

Physical Properties of PyrolusiteHide

Metallic, Dull, Earthy
Transparency:
Opaque
Colour:
Black or very dark grey.
Streak:
Black to bluish-black.
Hardness:
2 - 6½ on Mohs scale
Hardness Data:
Measured
Comment:
6 to 6.5 when crystalline, 2 when massive.
Tenacity:
Brittle
Cleavage:
Perfect
Perfect on {110}.
Fracture:
Irregular/Uneven
Density:
5.04 - 5.08 g/cm3 (Measured)    5.189 g/cm3 (Calculated)

Optical Data of PyrolusiteHide

Type:
Anisotropic
Anisotropism:
Strong, in yellows
Colour in reflected light:
Cream-white
Pleochroism:
Weak
Comments:
Very weak. Yellow to yellow-gray.

Chemical Properties of PyrolusiteHide

Formula:
MnO2

Crystallography of PyrolusiteHide

Crystal System:
Tetragonal
Class (H-M):
4/mmm (4/m 2/m 2/m) - Ditetragonal Dipyramidal
Space Group:
P42/mnm
Cell Parameters:
a = 4.4041(1) Å, c = 2.8765(1) Å
Ratio:
a:c = 1 : 0.653
Unit Cell V:
55.79 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Crystals are uncommon, either long or short prismatic parallel to [001] or equant; more typically found as earthy powder or fibrous aggregates as crusts on rocks; sometimes as botryoidal aggregates, more rarely as druses of microscopic crystals.
Never found as dendrites despite old literature. [The obsolete term "polianite" was once used to refer to crystalline pyrolusite, which was assumed to be a different species than earthy to crusty pyrolusite.]
Twinning:
Twinning rare. Repeated twins with twin planes {031} and {032}. Polysynthetic twinning observed in polished sections.

X-Ray Powder DiffractionHide

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Radiation - Copper Kα
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
d-spacingIntensity
3.11(100)
2.41(60)
2.11(20)
1.62(60)
1.56(10)
1.306(20)
1.304(20)
1.000(10)
Comments:
Data given are for synthetic material.

Synonyms of PyrolusiteHide

Other Language Names for PyrolusiteHide

Varieties of PyrolusiteHide

Argentiferous PyrolusiteA silver-bearing variety of pyrolusite.
PolianiteThis term using for description of Pyrolusite pseudomorphoses after pseudoorthorombic Manganite crystals (really manganite has monoclinic structure).

Relationship of Pyrolusite to other SpeciesHide

Member of:
Other Members of this group:
ArgutiteGeO2Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm
CassiteriteSnO2Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm
ParatelluriteTeO2Tet.
PlattneritePbO2Tet. 4/mmm (4/m 2/m 2/m)
RutileTiO2Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm
StishoviteSiO2Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm
TripuhyiteFe3+Sb5+O4Tet.

Common AssociatesHide

Associated Minerals Based on Photo Data:
Goethite57 photos of Pyrolusite associated with Goethite on mindat.org.
Calcite34 photos of Pyrolusite associated with Calcite on mindat.org.
Quartz24 photos of Pyrolusite associated with Quartz on mindat.org.
Hematite15 photos of Pyrolusite associated with Hematite on mindat.org.
Baryte15 photos of Pyrolusite associated with Baryte on mindat.org.
Psilomelane10 photos of Pyrolusite associated with Psilomelane on mindat.org.
Manganite9 photos of Pyrolusite associated with Manganite on mindat.org.
Limonite8 photos of Pyrolusite associated with Limonite on mindat.org.
Rhodonite8 photos of Pyrolusite associated with Rhodonite on mindat.org.
Gold6 photos of Pyrolusite associated with Gold on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

4.DB.05ArgutiteGeO2Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm
4.DB.05CassiteriteSnO2Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm
4.DB.05PlattneritePbO2Tet. 4/mmm (4/m 2/m 2/m)
4.DB.05RutileTiO2Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm
4.DB.05TripuhyiteFe3+Sb5+O4Tet.
4.DB.05TugarinoviteMoO2Mon.
4.DB.05Varlamoffite(Sn,Fe)(O,OH)2
4.DB.10ByströmiteMgSb2O6Tet. 4/mmm (4/m 2/m 2/m) : P4/nmm
4.DB.10Tapiolite-(Fe)(Fe,Mn)(Ta,Nb)2O6Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm
4.DB.10Tapiolite-(Mn)(Mn,Fe)(Ta,Nb)2O6Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm
4.DB.10OrdoñeziteZnSb2O6Tet.
4.DB.15bAkhtenskiteε-Mn4+O2Hex. 6/mmm (6/m 2/m 2/m) : P63/mmc
4.DB.15cNsutite(Mn4+,Mn2+)(O,OH)2Hex.
4.DB.15aParamontroseiteV4+O2Orth.
4.DB.15aRamsdelliteMn4+O2Orth. mmm (2/m 2/m 2/m)
4.DB.20Scrutinyiteα-PbO2Orth.
4.DB.25IshikawaiteU4+Fe2+Nb2O8Mon.
4.DB.25Ixiolite(Ta,Nb,Sn,Fe,Mn)4O8Orth.
4.DB.25Samarskite-(Y)(Y,Fe3+,Fe2+,U,Th,Ca)2(Nb,Ta)2O8Orth. mmm (2/m 2/m 2/m) : Pbcn
4.DB.25SrilankiteZrTi2O6Orth. mmm (2/m 2/m 2/m) : Pbcn
4.DB.25Yttrocolumbite-(Y)Y(U4+,Fe2+)Nb2O8
4.DB.25Calciosamarskite(Ca,Fe3+,Y)2(Nb,Ta,Ti)2O8Mon.
4.DB.25Samarskite-(Yb)(Yb,Y,Fe3+,Fe2+,U,Th,Ca)2(Nb,Ta)2O8Mon. 2/m : P2/b
4.DB.30FerberiteFeWO4Mon. 2/m : P2/b
4.DB.30HübneriteMnWO4Mon. 2/m : P2/b
4.DB.30Sanmartinite(Zn,Fe)WO4Mon. 2/m : P21/b
4.DB.30KrasnoselskiteCoWO4Mon.
4.DB.30HeftetjerniteScTaO4Mon. 2/m
4.DB.30HuanzalaiteMgWO4Mon. 2/m : P2/b
4.DB.35Columbite-(Fe)FeNb2O6Orth. mmm (2/m 2/m 2/m) : Pbcn
4.DB.35Tantalite-(Fe)FeTa2O6Orth. mmm (2/m 2/m 2/m) : Pbcn
4.DB.35Columbite-(Mn)(Mn,Fe)(Nb,Ta)2O6Orth. mmm (2/m 2/m 2/m) : Pbcn
4.DB.35Tantalite-(Mn)MnTa2O6Orth. mmm (2/m 2/m 2/m) : Pbcn
4.DB.35Columbite-(Mg)(Mg,Fe,Mn)(Nb,Ta)2O6Orth.
4.DB.35Qitianlingite(Fe,Mn)2(Nb,Ta)2WO10Orth.
4.DB.35Magnocolumbite(Mg,Fe,Mn)(Nb,Ta)2O6
4.DB.35Tantalite-(Mg)(Mg,Fe2+)(Ta,Nb)2O6Orth. mmm (2/m 2/m 2/m)
4.DB.40FerrowodginiteFe2+Sn4+Ta2O8Mon.
4.DB.40LithiotantiteLiTa3O8Mon.
4.DB.40LithiowodginiteLiTa3O8Mon.
4.DB.40TitanowodginiteMn2+TiTa2O8Mon.
4.DB.40WodginiteMn2+Sn4+Ta2O8Mon.
4.DB.40FerrotitanowodginiteFe2+TiTa2O8Mon.
4.DB.40WolframowodginiteMn(Mn,Sn,Fe,Ta)(W,Ta,Nb)2O8
4.DB.45TivaniteV3+TiO3(OH)Mon.
4.DB.50Carmichaelite(Ti,Cr,Fe)[O2-x(OH)x]Mon. 2/m : P21/b
4.DB.55AlumotantiteAlTaO4Orth. mmm (2/m 2/m 2/m) : Pbcn
4.DB.60Biehlite((Sb,As)O)2[MoO4]Mon.

Related Minerals - Dana Grouping (8th Ed.)Hide

4.4.1.1RutileTiO2Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm
4.4.1.2IlmenorutileFex(Nb,Ta)2x · 4Ti1-xO2Tet.
4.4.1.3Strüverite(Ti,Ta,Fe)O2
4.4.1.5CassiteriteSnO2Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm
4.4.1.6PlattneritePbO2Tet. 4/mmm (4/m 2/m 2/m)
4.4.1.7ArgutiteGeO2Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm
4.4.1.9StishoviteSiO2Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

7.18.1ManganositeMnOIso. m3m (4/m 3 2/m) : Fm3m
7.18.2HausmanniteMn2+Mn3+2O4Tet. 4/mmm (4/m 2/m 2/m) : I41/amd
7.18.4RamsdelliteMn4+O2Orth. mmm (2/m 2/m 2/m)
7.18.5Akhtenskiteε-Mn4+O2Hex. 6/mmm (6/m 2/m 2/m) : P63/mmc
7.18.6FeitknechtiteMn3+O(OH)Trig. 3m (3 2/m) : P3m1
7.18.7ManganiteMn3+O(OH)Mon. 2/m : P21/b
7.18.8GroutiteMn3+O(OH)Orth. mmm (2/m 2/m 2/m) : Pnma
7.18.9Nsutite(Mn4+,Mn2+)(O,OH)2Hex.
7.18.10PyrochroiteMn(OH)2Trig. 3m (3 2/m)
7.18.11Birnessite(Na,Ca)0.5(Mn4+,Mn3+)2O4 · 1.5H2OMon. 2/m : B2/m
7.18.12Aurorite(Mn2+,Ag,Ca)Mn4+3O7 · 3H2OTrig. 3 : R3
7.18.13CianciulliiteMn(Mg,Mn)2Zn2(OH)10 · 2-4H2OMon. 2/m : B2/m

Fluorescence of PyrolusiteHide

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for PyrolusiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Dana and Penfield (1888) American Journal of Science: 35: 243.
St. John (1923) Physical Reviews: 21: 389.
Ferrari (1926) Acc. Linc., Att.: 3: 224.
Vaux, G., Bennett, M.H. (1937) X-Ray Studies on Pyrolusite (Including Polianite) and Psilomelane. Mineralogical Magazine: 24: 521.
Palache, C., Berman, H., Frondel, C. (1944) The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Volume I: Elements, Sulfides, Sulfosalts, Oxides. John Wiley and Sons, Inc., New York. 7th edition, revised and enlarged: 562-566.
Neues Jahrbuch für Mineralogie, Monatshefte (1974) 8: 371-384.
Potter, R., Rossman, G. (1979) The Tetravalent Manganese Oxides: Identification, hydration and Structural Relationships by Infrared Spectroscopy. American Mineralogist: 64: 1199-1218.
Gaines, R.V., Skinner, H.C.W., Foord, E.E., Mason, B., Rosenzweig, A., King, V.T. (1997) Dana's New Mineralogy: The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana: 238.
Kohler, T., Armbruster, T., Libowitzky, E. (1997) Hydrogen bonding and Jahn-Teller distortion in groutite, α-MnOOH, and manganite, γ-MnOOH, and their relations to the manganese dioxides ramsdellite and pyrolusite. Journal of Solid State Chemistry: 133: 486-500.

Internet Links for PyrolusiteHide

Localities for PyrolusiteHide

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