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black, steel-grey
Named after the American mineralogist, Lewis S. Ramsdell (1895-1975), of the University of Michigan, who first described the mineral
Ramsdellite Group.

Forms by inversion of pyrolusite or oxidative dehydrogenation of groutite.

Classification of Ramsdellite

Approved, 'Grandfathered' (first described prior to 1959)

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 : AX2

7 : Oxides and Hydroxides
18 : Oxides of Mn

Physical Properties of Ramsdellite

Diaphaneity (Transparency):
black, steel-grey
brownish black, black
Hardness (Mohs):
4.37 g/cm3 (Measured)    4.79 g/cm3 (Calculated)

Chemical Properties of Ramsdellite

Elements listed in formula:

Crystallography of Ramsdellite

Crystal System:
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Cell Parameters:
a = 4.53 Å, b = 9.27 Å, c = 2.86 Å
a:b:c = 0.489 : 1 : 0.309
Unit Cell Volume:
V 120.43 ų
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.
X-Ray Powder Diffraction Data:
4.08 (10)
2.53 (8)
2.13 (5)
1.88 (5)
1.64 (6)
1.60 (7)
1.46 (5)

Type Occurrence of Ramsdellite

Relationship of Ramsdellite to other Species

Structurally related to group(s):
7.18.11Birnessite(Na,Ca,K)0.6(Mn4+,Mn3+)2O4 · 1.5H2O
7.18.12Aurorite(Mn2+,Ag,Ca)Mn34+O7 · 3H2O
7.18.13CianciulliiteMg2Mn2+Zn2(OH)10 · 2-4H2O

Other Names for Ramsdellite

Name in Other Languages:
Simplified Chinese:斜方锰矿

Other Information

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 Ramsdellite

Reference List:
American Mineralogist(1962): 47: 47-58.

American Mineralogist(1979): 64: 1199-1218.

Zeitschrift für Kristallographie (1994): 209: 941.

Kohler, T., Armbruster, T., and 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 Ramsdellite URL:
Please feel free to link to this page.
The following Ramsdellite specimens are currently listed for sale on

Localities for Ramsdellite

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.
(TL) indicates type locality for a valid mineral species. (FRL) indicates first recorded locality for everything else. ? 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.
  • New South Wales
    • Yancowinna Co.
Worner, H. K. and Mitchell, R. W., eds. Birch, W. D. (et al) (1982) Minerals of Broken Hill, published by Australian Mining & Smelting Limited ISBN 0-909221-18-9
  • South Australia
    • Eyre Peninsula
      • Middleback Range
        • Iron Knob
No reference listed
  • Göygöl District (Hanlar)
Pavel M. Kartashov data
  • Haskovo Oblast (Khaskovo Oblast)
    • Rhodope Mts
I. Kostov, V. Breskovska, J. Mincheva-Stefanova, G. Kirov (1964): Minerals of Bulgaria. Sofia, Bulgaria, 540 pp. (in Bulgarian).
Burkina Faso
  • Centre-Nord Region
Hénocque, O., Ruffet, G., Colin, F., & Féraud, G. (1998). < sup> 40 Ar/< sup> 39 Ar dating of West African lateritic cryptomelanes. Geochimica et Cosmochimica Acta, 62(16), 2739-2756.
  • Nova Scotia
    • Hants Co.
      • Walton
R.W. Boyle, "The Geology, Geochemistry, and Origin of the Barite, Manganese, and Lead-Zinc-Copper-Silver Deposits of the Walton-Cheverie Area, Nova Scotia", Geological Survey of Canada, Bulletin 166, 1972.
    • Kings Co.
      • Bay of Fundy
Canadian Mineralogist 9 (1969) 718-720.
    • Pictou Co.
Fleischer, M., Richmond, W.E, and Evans H.T. Jr., "Studies of the Manganese Oxides. V. Ramsdellite, MnO2, an Orthorhombic Dimorph of Pyrolusite", The American Mineralogist, vol. 47, pg. 47, Jan-Feb 1962.
  • Atacama Region
    • Chañaral Province
      • Caballo Muerto district
Maurizio Dini - analysed material by Bob Jenkins
Czech Republic
  • Bohemia (Böhmen; Boehmen)
    • Karlovy Vary Region
      • Krušné Hory Mts (Erzgebirge)
        • Jáchymov District (St Joachimsthal)
          • Horní Blatná District (Platten)
            • Horní Blatná (Platten; Bergstadt Platten)
Bufka, A., Velebil, D.: Manganová mineralizace žíly Marie Terezie u Horní Blatné v Krušných horách. Bulletin mineralogicko-petrografického oddělení Národního muzea v Praze, 2003, roč. 11, s. 100-114.
  • Bourgogne-Franche-Comté
    • Haute-Saône
      • Faucogney-et-la-Mer
        • Esmoulières
          • Saphoz
Wittern, Journée: "Mineralien finden in den Vogesen", von Loga (Cologne), 1997
Perseil, E. A. (1975) - Nature and mineralogical studies of manganese oxides and carbonates in Faucogney (Haute-Saone). Comptes Rendus des Séances de l'Académie des Sciences, D, 280, 1931-1934
Perseil, E. A. (1975) - Nature and mineralogical studies of manganese oxides and carbonates in Faucogney (Haute-Saone). Comptes Rendus des Séances de l'Académie des Sciences, D, 280, 1931-1934
  • Grand Est
    • Haut-Rhin
Wittern, Journée: "Mineralien finden in den Vogesen", von Loga (Cologne), 1997
  • Nouvelle-Aquitaine
    • Creuse
      • Soumans
        • Montebras
Patureau, J., Chiappero, P-J. & Lebocey, J. (2011): Mines et minéraux de Montebras, Soumans, Creuse. Le Règne Minéral. 99, 5-33
  • Occitanie
    • Ariège
Perseil, E. A. (1967): Manganese mineralization of the Upper Devonian in Las Cabesses (Ariege). Comptes Rendus du Congres National des Societes Savantes, Section des Sciences 91 (Part 2), 313-321.
    • Hautes-Pyrénées
Le Règne Minéral 47: 5-21
        • Vielle-Aure
DE ASCENCAO GUEDES R., TIXADOR Y., CASTERET A. & GOUJOU JC. (2002) La mine de Coustou, Vielle-Aure, Hautes-Pyrénées. Le Règne Minéral, 47, 23-31. (in french)
  • Baden-Württemberg
    • Black Forest
      • Gengenbach
        • Haigerach valley
Wittern,A. (1995) Mineralien finden im Schwarzwald
      • Wolfach
        • Oberwolfach
          • Rankach valley
Walenta, K. (1992): Die Mineralien des Schwarzwaldes. Chr. Weise Verlag, München, 336 pp. (in German)
    • Odenwald
      • Heidelberg
        • Mauer
S. Weiss: "Mineralfundstellen, Deutschland West", Weise (Munich), 1990
  • Lower Saxony
    • Harz
      • Bad Grund
        • Iberg
Schnorrer, G. & Klänhardt, K. (2002): Die Minerale des Iberg-Winterberg-Massives bei Bad Grund/Harz. Aufschluss, 53 (4), 181-199; Jahn, S., K. Stedingk & K. Klänhardt (2012): Das Iberg-Winterberg-Massiv bei Bad Grund. Mineralien-Welt, 23 (4), 30-67.
    • Peine
Weiss: "Mineralfundstellen, Deutschland West", Weise (Munich), 1990
  • Thuringia
    • Wurzbach
      • Weitisberga
Wittern: "Mineralfundorte in Deutschland", 2001
  • Western Region
    • Tarkwa
Mücke, A., Dzigbodi-Adjimah, K., and Annor, A. (1999): Mineralium Deposita 34, 297-311.
  • Aegean Islands Department (Aiyaíon)
    • Kykládes Prefecture
      • Cyclade Islands (Cyclades; Kikladhes; Nomos Kikladhon)
        • Milos Island (Melos)
Hein, J. R.; Stamatakis, M. G.; Dowling, J. S. (2000): Trace metal-rich Quaternary hydrothermal manganese oxide and barite deposit, Milos Island, Greece. Transactions of the Institution of Mining and Metallurgy, 109, B67-B76.
KILIAS, S. P. (2012). MICROBIAL MAT–RELATED STRUCTURES IN THE QUATERNARY CAPE VANI MANGANESE-OXIDE (-BARITE) DEPOSIT, NW MILOS ISLAND, GREECE. Microbial Mats in Siliciclastic Depositional Systems Through Time, SEPM (Society for Sedimentary Geology) Special Publication, 101, 97-100.
  • Attikí Prefecture (Attica; Attika)
    • Lavrion District (Laurion; Laurium)
      • Lavrion District Mines
        • Agios Konstantinos [St Constantine] (Kamariza)
No reference listed
        • Daskalio area
Hanke, H. (1996): Neues aus Lavrion (II). Mineralien-Welt, 7 (1), 54-56.
  • Borsod-Abaúj-Zemplén Co.
    • Bükk Mts
      • Bükkszentkereszt
Koch: Minerals of Hungary, 1985
    • Zemplén Mts (Tokaj Mts)
      • Erdőhorváti
GEODA, 1999
  • Veszprém Co.
    • Bakony Mts
      • Eplény
Szakáll & Gatter, 1993
      • Úrkút
        • Csárda Hill
Szakáll & Jánosi (1996) The Minerals of Hungary
  • Andhra Pradesh
    • Adilabad District
Rao, J. S. R. Krishna; Kasipathi, C. (1985): Occurrence of todorokite from Adilabad Manganese Mines, Andhra Pradesh. Current Science 54, 862.
    • Vizianagaram District
Econ Geol (1980) 75:1083-1104
Econ Geol (1980) 75:1083-1104
  • Karnataka
    • Bellary District
      • Bellary-Hospet iron belt
        • Sandur
Rao, J. S. R. K., Naidu, B. V. & Rao, K. V. (1979): Ore microscopic, x-ray and trace elemental data on manganese ores from Sandur, Karnataka, India. Acta Mineralogica-Petrographica 24, 91-97.
  • Liguria
    • La Spezia Province
      • Vara Valley
        • Borghetto Vara
  • Veneto
    • Verona Province
      • Negrar
        • Montecchio
          • Vajo Siresol
Probed by Prof. Giuseppetti; Boscardin, M. (2014): Provincia di Verona. In: Zorzi, F., Boscardin, M. (eds.), Minerali del Veneto. Alla scoperta sei tesori della nostra regione. Museo di Storia Naturale e Archeologia di Montebelluna - Treviso, Cierre Edizioni, Sommacampagna, 153-171.
    • Vicenza Province
      • Lusiana
Boscardin M., Daleffe A., Rocchetti I., Zordan A. “I minerali nel Vicentino”, Museo “G. Zannato”, Montecchio Maggiore (Vicenza), 2011.
  • Hokkaido
    • Oshima peninsula
      • Hiyama Subprefecture
        • Imakane (Imagane; Hanaishi)
Miura, Hiroyuki;Kudou, Haruhiko;Choi, Jai Ho;Hariya, Yu (1990) The Crystal Structure of Ramsdellite from Pirika Mine. Journal of the Faculty of Science, Hokkaido University. Series 4, Geology and mineralogy; Vol.XXII, No.4
  • Honshu Island
    • Chubu Region
      • Niigata Prefecture
        • Niigata City
University of Tokyo collection
      • Shizuoka prefecture
        • Shimoda City
Alfredo Petrov specimens
    • Tohoku Region
      • Akita Prefecture
        • Kitaakita City
          • Ani-machi
Dr. Matsuo Nambu ore collection (curated at Geological Survey of Japan)
      • Iwate Prefecture
        • Kuji City
          • Yamagata
Nambu, M. & Tanida, K. (1961): On the progressive alteration of manganese dioxide minerals in the Toyoguchi Mine, Iwate Prefecture. Ganseki Kobutsu Kosho Gakkaishi 45, 39-48. (in Japanese)
        • Kunohe-gun
          • Noda-mura
Watanabe, T. (1959) Mineralogical Journal, 2, 6, 408-421
  • Baja California (Baja California Norte; BC Norte)
    • Mun. de Ensenada
Panzcer (1987), pp. 103, 143, 150, 165, 174, 1777, 180, 186, 192, 226, 290, 319, 327, 334
Panzcer, 1987, p. 327
    • Mun. de Tecate
      • Los Gavilanes
[MinRec 14:110, 14:112]
  • Baja California Sur (BC Sur)
    • Mun. de Mulegé
      • Lucifer (San Lucifer)
Panczner (1987): 327.
  • Chihuahua
    • Mun. de Ahumada
Finkleman et al. (1974) Min. Magazine v. 39 pp. 549-558
    • Mun. de Aldama
Cross, B. & Culp Zeitner J. (2006), Geodes Natures Treasures, P.21
    • Mun. de Aquiles Serdán
      • Santa Eulalia District
        • East Camp
Megaw, P.K.M., 1990b, Geology and geochemistry of the Santa Eulalia mining district, Chihuahua, Mexico.: Unpublished Ph.D. Thesis, Univ. of Arizona, 549 p
  • Durango
    • Mun. de Mapimí
      • Mapimí
Rocks & Min.: 56:247.
Panczner (1987): 327.
New Caledonia
  • Northern Province
    • Houaïlou Commune
Berger, V.I., Singer, D.A., Bliss, J.D., and Moring, B.C., 2011, Ni-Co laterite deposits of the world; database and grade and tonnage models: U.S. Geological Survey Open-File Report 2011-1058.
  • Telemark
    • Notodden
Selbekk R.S. (2010): Norges mineraler. En revidert utgave av Norges mineraler (Neumann 1985). Tapir-NGU-NHM. 552p (p.151)
  • Vest-Agder
    • Kristiansand
Neumann, H. (1985): Norges Mineraler. Norges geologiske Undersøkelse Skrifter 68, p. 74; Breivik, H. ; Myre, K. & Larsen, A. O. (2007): Manganforekomster på Sørlandet: Kvivikdalen (Kostøl, Ålefjær): Norsk Bergverksmuseums Skrift, 35, 25-31
    • Mandal
Neumann, H. (1959): Contributions to the mineralogy of Norway No. 1. An introduction. Norsk Geologisk Tidsskrift 39:231-236
  • Guarda District
    • Gouveia
      • Folgosinho
    • Sabugal
      • Bendada
Schnorrer-Köhler (1991), Mineral Occurrences.
  • Setúbal District
    • Santiago do Cacém
      • Cercal
Martins da Pedra collection
  • Suceava Co.
    • Suceava district
      • Iacobeni (Jakobeny; Jacobeny; Jakabfalva)
South Africa
  • Northern Cape Province
    • Kalahari manganese field
      • Hotazel
Wilson, W.E. & Dunn, P.J., (1978) Famous localities: The Kalahari manganese field. Mineralogical Record 9(3) 137-153; Cairncross, B. and Dixon, R., (1995) Minerals of South Africa. The Geological Society of South Africa: pp 237.
Minerals of South Africa
      • Western Belt
Gutzmer, J. (1996). Genesis and alteration of the Kalahari and Postmasburg manganese deposits, Griqualand West, South Africa (Doctoral dissertation, Rand Afrikaans University).
  • Dalsland
    • Åmål
      • Strandhem ore field
Kjell Gatedal
  • Wallis (Valais)
    • Turtmann Valley
      • Pipjitälli
Ansermet, S. (2012): Mines et minéraux du Valais - II. Anniviers et Tourtemagne. With contributions by N. Meisser, Ed. Porte-plumes (Ayer)
  • Wales
    • Ceredigion
      • Trefeirig
        • Ponterwyd
          • Nant-y-Moch Reservoir area
T.F. Cotterell, unpublished data
  • Arizona
    • Maricopa Co.
      • Vulture Mts
        • Vulture District
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 351; Hewett, D.F. (1964), Veins of hypogene manganese oxide minerals in the southwestern US, Econ.Geol.: 59: 1429-1472.
    • Mohave Co.
Anthony, J.W., et al (1995), Mineralogy of AZ, 3rd. ed.: 188; Mouat, M.M. (1962), Mn Oxides from the Artillery Mts area, AZ, Am.Min.: 47: 744-757.
        • Artillery Peak
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 351.; Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 252, 351.
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd. ed.: 252, 351.
Anthony, J.W., et al (1995), Mineralogy of AZ, 3rd.ed.: 351; Mouat, M.M. (1962), Manganese oxides from the Artillery Mountains area, AZ, Am.Min.: 47:744-757.
    • Pinal Co.
      • Dudleyville
        • Malpais Hill
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd. ed.: 160, 250; Bideaux, R.A., et al (1960), Some new occurrences of minerals of AZ, AZ Geol. Soc. Digest: 3: 53-56; Thomssen, R.W. (1983), The minerals of Malpais Hill, Pinal Co., AZ, Min.Rec.: 14: 109-113.
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd. ed.: 351; Thomssen, R.W. (1983), The minerals of Malpais Hill, Pinal Co., AZ, Min.Rec.: 14: 109-113.
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd. ed.: 160, 250; Bideaux, R.A., et al (1960), Some new occurrences of minerals of AZ, AZ Geol. Soc. Digest: 3: 53-56; Thomssen, R.W. (1983), The minerals of Malpais Hill, Pinal Co., AZ, Min.Rec.: 14: 109-113.
      • Mammoth District
        • Tiger
          • St. Anthony deposit
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 351; Bideaux, R.A. (1980), Tiger, AZ, Min.Rec.: 11: 155-181.
    • Yavapai Co.
      • Box Canyon District
        • Sam Powell Peak
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 342-343, 351; Wilkinson, W.H., Jr., et al (1983), Ramsdellite from the Mistake Mine, Min.Rec.: 14: 333-335.
      • Weaver Mts
        • Weaver District (Virginia District; Mocking Bird District)
          • Octave
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 351.
  • California
    • Imperial Co.
      • Chocolate Mts
        • Paymaster District
Hadley, Jarvis Bardwell (1942), Manganese deposits in the Paymaster mining district, Imperial County, California: USGS Bulletin 931-S: 465; Hewett, Donnel Foster (1964), Veins of hypogene manganese oxide minerals in the southwestern United States: Economic Geology: 59: 1440; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 318; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 164.
  • Colorado
    • Saguache Co.
Rocks & Minerals (July-August, 2002)
  • Montana
    • Granite Co.
      • Philipsburg District (Flint Creek District)
Geology and Ore Deposits of the Philipsburg District, Granite Co., Montana; William C. Prinz, 1967
    • Silver Bow Co.
The mineralogy of the butte district, Montana By John M. Guilbert and Lester G. Zeihen; "Butte, Montana, Minerals, Mines and History", The Mineralogical Record, Vol 33, No. 1, Jan-Feb, 2002
  • New Mexico
    • Sierra Co.
Minerals of New Mexico 3rd ed.
      • Iron Mountain No. 2 District
Minerals of New Mexico 3rd ed.
Northrop, Minerals of New Mexico, 3rd Rev. Ed., 1996
    • Socorro Co.
Minerals of New Mexico 3rd ed.
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