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Pyrochroite

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Långban, Filipstad, Värmland, Sweden
© Thomas Witzke

Show Pyrochroite Photos (7)
Formula:
Mn(OH)
 
2
System:TrigonalColour:Colourless, greenish, ...
Hardness:2½ - 3
Name:From the Greek for "fire" and "color" in allusion to the change of color upon ignition.


Brucite Group

Classification of Pyrochroite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:4/F.03-30
Nickel-Strunz 10th (pending) edition ID:4.FE.05

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
E : Hydroxides with OH, without H2O; sheets of edge-sharing octahedra
Dana 8th edition ID:6.2.1.3

6 : HYDROXIDES AND OXIDES CONTAINING HYDROXYL
2 : X(OH)2
Hey's CIM Ref.:7.18.10

7 : Oxides and Hydroxides
18 : Oxides of Mn
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Type Occurrence of Pyrochroite

Type Locality:Pajsberg mine, Pajsberg, Filipstad, Värmland, Sweden
Year of Discovery:1864

Physical Properties of Pyrochroite

Lustre:Pearly
Diaphaneity (Transparency):Translucent, Translucent on thin edges, Opaque
Colour:Colourless, greenish, bluish (fresh), brown to black (exposed); flesh-red or amethystine inn transmitted light
Hardness (Mohs):2½ - 3
Tenacity:Elastic
Cleavage:Perfect
On {0001}
Density (measured):3.23 - 3.27 g/cm3
Density (calculated):3.25 g/cm3

Crystallography of Pyrochroite

Crystal System:Trigonal
Class (H-M):3m (3 2/m) - Hexagonal Scalenohedral
Cell Parameters:a = 3.31Å, c = 4.74Å
Ratio:a:c = 1 : 1.432
Unit Cell Volume:V 44.97 ų (Calculated from Unit Cell)
Morphology:Crystals tabular {0001}; also less commonly rhombohedral with large {101¯2} or {101¯1}. Rarely prismatic [0001] with {112¯0} and {0001} developed. Fliated masses.

Optical Data of Pyrochroite

Type:Uniaxial (-)
RI values: nω = 1.680 - 1.681 nε = 1.720 - 1.723
Maximum Birefringence:δ = 0.040

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:High
Pleochroism:Visible
Comments:Dichroic: O = brown; E = lighter brown.
Comments:Strongly reflecting in polished section (black altered material).

Chemical Properties of Pyrochroite

Formula:
Mn(OH)
 
2
Essential elements:H, Mn, O
All elements listed in formula:H, Mn, O

Relationship of Pyrochroite to other Species

Related Minerals - Nickel-Strunz Grouping):
4.FE.05Amakinite
(Fe
2+
 
,Mg)(OH)
 
2
4.FE.05Brucite
Mg(OH)
 
2
4.FE.05Portlandite
Ca(OH)
 
2
4.FE.05Theophrastite
Ni(OH)
 
2
4.FE.10Bayerite
Al(OH)
 
3
4.FE.10Doyleite
Al(OH)
 
3
4.FE.10Gibbsite
Al(OH)
 
3
4.FE.10Nordstrandite
Al(OH)
 
3
4.FE.15Böhmite
AlO(OH)
4.FE.15Lepidocrocite
γ-Fe
3+
 
O(OH)
4.FE.20Grimaldiite
CrO(OH)
4.FE.20Heterogenite
CoO(OH)
4.FE.25Feitknechtite
Mn
3+
 
O(OH)
4.FE.25Lithiophorite
(Al,Li)MnO
 
2
(OH)
 
2
4.FE.30Quenselite
PbMnO
 
2
(OH)
4.FE.35Ferrihydrite
Fe
 
5
O
 
3
(OH)
 
9
4.FE.40Feroxyhyte
Fe
3+
 
O(OH)
4.FE.40Vernadite
(Mn
4+
 
,Fe
3+
 
,Ca,Na)(O,OH)
 
2
 · nH
 
2
O
4.FE.45Quetzalcoatlite
Zn
 
6
Cu
 
3
(TeO
 
6
)
 
2
(OH)
 
6
·Ag
 
x
Pb
 
y
Cl
 
x+2y
Related Minerals - Hey's Index Grouping:
7.18.1Manganosite
MnO
7.18.2Hausmannite
MnMn
 
2
O
 
4
7.18.3Pyrolusite
MnO
 
2
7.18.4Ramsdellite
Mn
4+
 
O
 
2
7.18.5Akhtenskite
ε-Mn
4+
 
O
 
2
7.18.6Feitknechtite
Mn
3+
 
O(OH)
7.18.7Manganite
Mn
3+
 
O(OH)
7.18.8Groutite
Mn
3+
 
O(OH)
7.18.9Nsutite
(Mn
4+
 
,Mn
2+
 
)(O,OH)
 
2
7.18.11Birnessite
(Na,Ca)
 
0.5
(Mn
4+
 
,Mn
3+
 
)
 
2
O
 
4
 · 1.5H
 
2
O
7.18.12Aurorite
(Mn
2+
 
,Ag,Ca)Mn
4+
3
O
 
7
 · 3H
 
2
O
7.18.13Cianciulliite
Mn(Mg,Mn)
 
2
Zn
 
2
(OH)
 
10
·2-4H
 
2
O

Other Names for Pyrochroite

Synonyms:
Eisenpyrochroite
German names:
Pyrochroit
Japanese names:
パイロクロアイト
Russian names:
Пирохроит
Spanish names:
Pyrochroita

Other Information

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

References for Pyrochroite

Reference List:Igelström (1864), Ann. Phys.: 122: 181.

Igelström (1864), Ak. Stockholm, Öfv.: 21: 205.

Flink (1886), Ak. Stockholm, Handl.: 12(2), n. 2: 2.

Flink (1900), Bull. Geol. Inst. Upsala: 5.

Sjogren (1905), Geol. För. Förh.: 27: 37.

Flink (1910), Ark. Kemi.: 3(35) 106.

Aminoff (1919), Geol. För. Förh.: 41: 407.

Flink (1919), Geol. För. Förh.: 41: 433 (as Eisenpyrochroite).

Palache, C (1935) The Minerals of Franklin andSterling Hill, New Jersey, USGS Professional Paper 180: 50.

Palache, Charles, Harry Berman & Clifford Frondel (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: 639-641.

American Mineralogist (1965): 50: 1296-1354.

Internet Links for Pyrochroite

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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Search for Pyrochroite in the Natural History Museum (London) online catalogue
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    Localities for Pyrochroite

    Hide Locality List
    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
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    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Canada
     
    • Québec
      • Richmond Co.
        • Shipton Township
          • Asbestos
    		[MinRec 10:76]
    China
     
    • Shaanxi Province
      • Hanzhong Prefecture
        • Ningqiang Co.
    		Yeh, H.-W., Hein, J.R., Ye, J., and Fan, D. (1999): Ore Geology Reviews 15(1), 55-69.
    Ghana
     
    • Western Province
      • Tarkwa
    		Mineralium Deposita Volume 34 Issue 3 (1999) pp 297-311
    Japan
     
    • Honshu Island
      • Chubu Region
        • Aichi Prefecture
          • Kita-Shidara-gun
            • Shidara
    		Mayumi Yoshinaga (1963) Memoirs of the Faculty of Science, Kyushu University, Series D, Geology, 14, 1, 1-22.
      • Chugoku Region
        • Yamaguchi Prefecture
          • Iwakuni City
    		Mayumi Yoshinaga (1963) Memoirs of the Faculty of Science, Kyushu University, Series D, Geology, 14, 1, 1-22.
    Mayumi Yoshinaga (1963) Memoirs of the Faculty of Science, Kyushu University, Series D, Geology, 14, 1, 1-22.
      • Kanto Region
        • Gunma Prefecture
          • Kiryuu City
        • Tochigi Prefecture
          • Kanuma
    		Mayumi Yoshinaga (1963) Memoirs of the Faculty of Science, Kyushu University, Series D, Geology, 14, 1, 1-22.
      • Kinki Region
        • Kyoto Prefecture
          • Sohraku-gun
        • Shiga Prefecture
    		No reference listed
      • Tohoku Region
        • Iwate Prefecture
          • Miyako City
    		Mayumi Yoshinaga (1963) Memoirs of the Faculty of Science, Kyushu University, Series D, Geology, 14, 1, 1-22.
    Namibia
     
    • Otjozondjupa Region
      • Grootfontein District
        • Kombat
    		Mineralogical Record: 22: 421.
    South Africa
     
    • Northern Cape Province
      • Kalahari manganese fields
        • Hotazel
    		[MinRec 22:289]
        • N'Chwaning Mines
    		[Von Bezing, K. L. et al. (1991) - The Kalahari (Afrique du Sud) manganese field : an update, Mineralogical Record, 22 (3), 279-302.]
    [MinRec 22:289]
    • Northwest Province
      • Western Bushveld Complex
        • Rustenburg District
          • Pilansberg Complex
    		The Canadian Mineralogist, V 42, 2004, pp. 1169-1178.
    Sweden
     
    • Dalarna
      • Hedemora
        • Garpenberg
    		Kjell Gatedal
    • Värmland
      • Filipstad
    		Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 927; Nysten, P., Holtstam, D. and Jonsson, E. (1999) The Långban minerals. In Långban - The mines,their minerals, geology and explorers (D. Holtstam and J. Langhof, eds.), Swedish Museum of Natural History and Raster Förlag, Stockholm & Chr. Weise Verlag, Munich, pp. 89-183.
    Kjell Gatedal
        • Nordmark
    		Min.Mag.(1978) 42, 133-136
    Kjell Gatedal
    Mineralogical Magazine (1998) 62 (3), 395-407
    Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 782; Anthony, Bideaux, Bladh, Nichols: "Handbook of Mineralogy", Vol. 4, 2000
        • Pajsberg
    		No reference listed
    [Am Min 50 (1965), 1296; MinRec 1:165]
    • Västmanland
      • Hällefors
        • Grythyttan
    		No reference listed
    Switzerland
     
    • St Gallen
      • Alvier Group
        • Sargans
    		Die Mineralien der Schweiz, M. Weibel et al. 1990
    UK
     
    • England
      • Devon
        • Dartmoor & Teign Valley District
          • Teign Valley
            • Doddiscombsleigh
    		Bernie Millington Collection
    • Wales
      • Gwynedd (Caernarvonshire)
        • Lleyn Peninsula
          • Llanfaelrhys
            • Rhiw
    		No reference listed
    USA
     
    • California
      • Alpine Co.
    		MinRec 22:29-42
    [MinRec 22:37]
      • Santa Clara Co.
        • San Jose
    		www.mineralsocal.org
    • Nevada
      • White Pine Co.
    		NBMG Spec. Pub. 31 Minerals of Nevada
    • New Jersey
      • Sussex Co.
        • Franklin Mining District
          • Franklin
    		Palache(1935):50.
    Palache(1935):50-52; Dunn(1995):Pt4:601-603.
    Palache(1935):50.
          • Ogdensburg
            • Sterling Hill
    		Palache(1935):50-52; Dunn(1995):Pt4:601-603.
    Mineral and/or Locality
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