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About FeitknechtiteHide

Walter Feitknecht
lead gray, brownish black
Resinous, Sub-Metallic, Dull, Earthy
Specific Gravity:
3.249 (Calculated)
Crystal System:
Named in 1965 by Owen P. Brickner in honor of Walter Feitknecht [December 14, 1899 Schüpfen, Switzerland - 1975 Bern, Switzerland], systematic researcher relating to manganese oxide minerals and professor of Chemistry, University of Bern, Bern, Switzerland and who first synthesized the compound.
Polymorph of:
Black replacement of pyrochroite that yielded a mixture of hausmannite and feitknechtite. A specimen of black pyrochroite from the type locality was submitted to the RRUFF Project for Raman spectroscopic examination. Pyrochroite was detected, but not hausmannite or feitknechtite (Heixong Yang, personal communication, 2015).

Classification of FeitknechtiteHide

First Published:

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

1 : XO(OH)

7 : Oxides and Hydroxides
18 : Oxides of Mn

Physical Properties of FeitknechtiteHide

Resinous, Sub-Metallic, Dull, Earthy
lead gray, brownish black
3.249 g/cm3 (Calculated)
ICDD lists D (measured and calculated) = 3.80. Could be an error

Optical Data of FeitknechtiteHide

Uniaxial (-)
RI values:
nω = 2.055 nε = 1.950
Max Birefringence:
δ = 0.105
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Very High

Chemical Properties of FeitknechtiteHide


Crystallography of FeitknechtiteHide

Crystal System:
Class (H-M):
3m (3 2/m) - Hexagonal Scalenohedral
Space Group:
Cell Parameters:
a = 3.32 Å, c = 4.71 Å
a:c = 1 : 1.419
Unit Cell V:
44.96 ų (Calculated from Unit Cell)
Hexagonal platelets; granular, earthy.
Space group for synthetic material.

X-Ray Powder DiffractionHide

Powder Diffraction Data:
4.62 (100)
2.635 (50)
2.360 (20b)
1.960 (10b)
1.550 (1)
1.500 (1)
ICDD 18-804 synthetic. Original data by Bricker (1965), but originally thought to be tetragonal.

Type Occurrence of FeitknechtiteHide

General Appearance of Type Material:
Black replacement of pyrochroite. May show trigonal platy appearance.
Geological Setting of Type Material:
Gossan zone of a manganiferous marble-hosted
Associated Minerals at Type Locality:
Bricker, O. (1965) Some stability relations in the system Mn−O2−H2O at 25◦ and one atmosphere total pressure. American Mineralogist: 50: 1296–1354.

Other Language Names for FeitknechtiteHide

Simplified Chinese:六方水锰矿
Traditional Chinese:六方水錳礦

Common AssociatesHide

Associated Minerals Based on Photo Data:
Rhodonite1 photo of Feitknechtite associated with Rhodonite on mindat.org.
Pyrochroite1 photo of Feitknechtite associated with Pyrochroite on mindat.org.
Tephroite1 photo of Feitknechtite associated with Tephroite on mindat.org.
Hausmannite1 photo of Feitknechtite associated with Hausmannite on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

4.FE.05BruciteMg(OH)2Trig. 3m (3 2/m) : P3m1
4.FE.05PortlanditeCa(OH)2Trig. 3m (3 2/m)
4.FE.05PyrochroiteMn(OH)2Trig. 3m (3 2/m)
4.FE.05TheophrastiteNi(OH)2Trig. 3m (3 2/m) : P3m1
4.FE.10BayeriteAl(OH)3Mon. 2/m : P21/m
4.FE.10GibbsiteAl(OH)3Mon. 2/m
4.FE.10NordstranditeAl(OH)3Tric. 1 : P1
4.FE.15BöhmiteAlO(OH)Orth. mmm (2/m 2/m 2/m)
4.FE.15Lepidocrociteγ-Fe3+O(OH)Orth. mm2 : Cmc21
4.FE.25Lithiophorite(Al,Li)MnO2(OH)2Trig. 3m (3 2/m) : R3m
4.FE.30QuenselitePbMnO2(OH)Mon. 2/m : P2/b
4.FE.40Vernadite(Mn4+,Fe3+,Ca,Na)(O,OH)2 · nH2OHex.
4.FE.45QuetzalcoatliteZn6Cu3(TeO6)2(OH)6 · AgxPbyClx+2yTrig. 3m (3 2/m) : P3m1

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

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
7.18.3PyrolusiteMn4+O2Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm
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
7.18.7ManganiteMn3+O(OH)Mon. 2/m : P21/b
7.18.8GroutiteMn3+O(OH)Orth. mmm (2/m 2/m 2/m) : Pnma
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 FeitknechtiteHide

Not fluorescent in ultraviolet

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 FeitknechtiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Feitknecht, W., Marti, W. (1945) Über die Oxydation von Mangan(II)-hydroxyd mit molekularem Sauerstoff. Helvetica Chimica Acta: 28: 129-148.
Frondel, C. (1953) New manganese oxides: hydrohausmannite and woodruffite. American Mineralogist: 38: 761–769. (hydrohausmannite = feitknechtite + hausmannite)
Feitknecht, W., Brunner, P., Oswald, H.R. (1962) Über den einfluss der feuchtigkeit auf die oxydation von manganhydroxid durch molekularen sauerstoff. Zeitschrift für Anorganishe und Allgemeine Chemie: 316: 154-160.
Bricker, O. (1965) Some stability relations in the system Mn−O2−H2O at 25◦ and one atmosphere total pressure. American Mineralogist: 50: 1296–1354.
Nambu, M., Tanida, K., Kitamura, T., Komura, T. (1969) Feitknechtite and its origin from Noda-Tamagawa mine, Iwate Prefecture, Japan. Ganseki Kobutsu Kosho Gakkaishi: 59(3): 91–107 (in Japanese).
(1970) Chemical Absracts: 72: 121 (abs. ref. 3).
Meldau, R., Newesley, H., Strunz, H. (1974) Zur Kristallchemie von Feitknechtit. Naturwissenschaften: 60(8): 387 (in German).
Luo, J., Segal, S.R., Wang, J.Y., Tian, Z.R., Suib, S.L. (1996) Synthesis, Characterization, and Reactivity of Feitknechtite. Materials Research Society Proceedings: 43: 3-8.
Roth P (2007) Feitknechtite. in Minerals first discovered in Switzerland and minerals named after Swiss individuals, Kristallografik Verlag (Achberg Germany): 180-181.
Grangeon, S., Warmont, F., Tournassat, C., Lanson, B., Lanson, M., Elkaïm, E., Claret, F. (2017) Nucleation and growth of feitknechtite from nanocrystalline vernadite precursor. European Journal of Mineralogy: 29: 767-776.

Internet Links for FeitknechtiteHide

Localities for FeitknechtiteHide

This 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.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
  • Aichi
    • Kita-Shidara-gun
      • Shidara-cho
Yamada collection (Crystal World, Japan)
  • Iwate
    • Kuji City
      • Yamagata
Dr. Matsuo Nambu collection (curated at Geological Survey of Japan)
    • Kunohe-gun
      • Noda-mura
Rocks & Min.:59:216.
  • Nagano
    • Kamiina district
      • Hamayokokawa mine (Hamayokogawa mine)
Akira Kato (2011) Explanations of distributed specimens at the Ordinary Meeting of Mumeikai Group, No. 34 (January, 20011).
Akira Kato (2011) Explanations of distributed specimens at the Ordinary Meeting of Mumeikai Group, No. 34 (January, 20011).
  • Oita
    • Tsukumi
Minerals Unlimited specimens (Ridgecrest, California)
  • Shiga
    • Ritto City
Forrest Cureton specimens
  • Tochigi
    • Kanuma City
Akira Kato (undated manuscript): Country rock and Minerals of the Kaso mine, Kanuma City, Tochigi Prefecture. (in japanese)
  • Durango
    • Mapimí Municipality
      • Mapimí
Mineralogical Record (2003) 34:5 The Ojuela Mine
Panczner (1987): 191.
South Africa
  • Northern Cape
    • Kalahari manganese field
      • Hotazel
XRD by John Attard; Beukes, N. J., Burger, A. M., & Gutzmer, J. (1995). Fault-controlled hydrothermal alteration of Palaeoproterozoic manganese ore in Wessels Mine, Kalahari manganese field. South African Journal of Geology, 98(4), 430-451.
Minerals of South Africa
  • Dalarna County
    • Hedemora
      • Garpenberg
(Kjell Gatedal)+ Grensman, F., Kalinowski, M.P. and Sandström, F. (2001): Garpenberg Norra. Litofilen. 18 (2), 26-46.
  • Örebro County
    • Hällefors
      • Grythyttan
Moore, P. B. (1972). III. On Igelström's Manganese Arsenates and Antimonates from the Sjö Mine, Grythyttan, Örebro County, Sweden. GFF, 94(3), 423-434.
  • Värmland County
    • Filipstad
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.
      • Nordmark Odal Field (Nordmarksberg)
Langhof, J. (1998) Akrochordit från Nordmark. Långbansnytt. vol 12. [ reprinted in: Långbansnytt. De första 20 åren 1983-2003. Långbansällskapet - Skrifter och rapporter. 2, 42-43]
  • St. Gallen
    • Alvier Group
      • Sargans
Roth, P. & Meisser, N. (2013): Die seltenen Mineralien der Bündner Manganvorkommen. Schweizer Strahler 47 (3), 8-21 (in German and French).
  • Wales
    • Gwynedd
      • Lleyn Peninsula
        • Llanfaelrhys
          • Rhiw
UK Journal of mines & Minerals, number 29 pp47-48
  • New Jersey
    • Sussex Co.
      • Franklin Mining District
        • Franklin
Frondel, C.: Am. Min.:38:761-769 (1953); Wadsley, A.D.: Am. Min.:40:349-353 (1955); Dunn(1995):Pt4:591-592.
Mineral and/or Locality  
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