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Mg6Fe23+(OH)16(CO3) · 4H2O
White, yellowish green, ...
Vitreous, Waxy, Pearly
Named for the structural relationship to pyroaurite. Originally named sjögrenite by Clifford Frondel in 1940 in honor of Stens Anders Hjalmar Sjögren (1856-1922), Professor of Mineralogy, University of Stockholm, Sweden.
A polytype of Pyroaurite

Originally named sjögrenite. Recognised as a polytype of pyroaurite and accordingly discredited (Mills et al., 2012).

Often intergrown with pyroaurite-2H.

Classification of Pyroaurite-2H

Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"

D : Carbonates with additional anions, with H2O
A : With medium-sized cations

6 : AmBn(XO3)pZqxH2O & with (m+n):p = 8:1

11 : Carbonates
13 : Carbonates of Fe URL:
Please feel free to link to this page.

Type Occurrence of Pyroaurite-2H

Physical Properties of Pyroaurite-2H

Vitreous, Waxy, Pearly
Diaphaneity (Transparency):
White, yellowish green, brownish green, yellowish white, brownish white
Hardness (Mohs):
2.08 - 2.14 g/cm3 (Measured)    2.11 g/cm3 (Calculated)

Crystallography of Pyroaurite-2H

Crystal System:
Class (H-M):
6/mmm (6/m 2/m 2/m) - Dihexagonal Dipyramidal
Space Group:
Cell Parameters:
a = 3.113(3) Å, c = 15.61(1) Å
a:c = 1 : 5.014
Unit Cell Volume:
V 131.01 ų (Calculated from Unit Cell)
Thin plates {0001}, with a hexagonal outline and striated and indistinct lateral faces.
Z = 1/4
X-Ray Powder Diffraction Data:
7.78 (10)
3.90 (6)
2.65 (4)
2.54 (5)
2.39 (3)
2.21 (5)
1.87 (5)

Optical Data of Pyroaurite-2H

Uniaxial (-)
RI values:
nω = 1.573 nε = 1.550
Max Birefringence:
δ = 0.023
Image shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:

Chemical Properties of Pyroaurite-2H

Mg6Fe23+(OH)16(CO3) · 4H2O
All elements listed in formula:

Relationship of Pyroaurite-2H to other Species

Other Members of Group:
DesautelsiteMg6Mn23+(OH)16[CO3] · 4H2O
DroninoiteNi6Fe32+(OH)16Cl2 · 4H2O
HydrotalciteMg6Al2(OH)16[CO3] · 4H2O
IowaiteMg6Fe23+(OH)16Cl2 · 4H2O
MeixneriteMg6Al2(OH)16(OH)2 · 4H2O
Pyroaurite-3RMg6Fe23+(OH)16[CO3] · 4H2O
ReevesiteNi6Fe23+(OH)16(CO3) · 4H2O
StichtiteMg6Cr2(OH)16[CO3] · 4H2O
TakoviteNi6Al2(OH)16[CO3] · 4H2O
WoodalliteMg6Cr2(OH)16Cl2 · 4H2O
5.DA.05DypingiteMg5(CO3)4(OH)2 · 5H2O
5.DA.05GiorgiositeMg5(CO3)4(OH)2 · 5-6H2O
5.DA.05HydromagnesiteMg5(CO3)4(OH)2 · 4H2O
5.DA.05WidgiemoolthaliteNi5(CO3)4(OH)2 · 5H2O
5.DA.05UM1986-10-CO:ClHMgMnZnMg5(Zn,Mn)3(CO3)2(OH,Cl)12 · H2O
5.DA.05UM1987-01-CO:HMgSMg4(CO3)2(OH)2 · 6H2O ?
5.DA.10ArtiniteMg2(CO3)(OH)2 · 3H2O
5.DA.10IndigiriteMg2Al2(CO3)4(OH)2 · 15H2O
5.DA.10ChlorartiniteMg2(CO3)(OH)Cl · 2H2O
5.DA.15OtwayiteNi2(CO3)(OH)2 · H2O
5.DA.15ZaratiteNi3(CO3)(OH)4 · 4H2O
5.DA.20KambaldaiteNaNi4(CO3)3(OH)3 · 3H2O
5.DA.25CallaghaniteCu2Mg2(CO3)(OH)6 · 2H2O
5.DA.30Claraite(Cu,Zn)3(CO3)(OH)4 · 4H2O
5.DA.35HydroscarbroiteAl14(CO3)3(OH)36 · nH2O
5.DA.35ScarbroiteAl5(CO3)(OH)13 · 5H2O
5.DA.40CaresiteFe42+Al2(OH)12[CO3] · 3H2O
5.DA.40QuintiniteMg4Al2(OH)12[CO3] · 3H2O
5.DA.40CharmariteMn42+Al2(OH)12[CO3] · 3H2O
5.DA.45Stichtite-2HMg6(Cr,Al)2(CO3)(OH)16 · 4H2O
5.DA.45BrugnatelliteMg6Fe3+(CO3)(OH)13 · 4H2O
5.DA.45ChlormagaluminiteMg4Al2(OH)12Cl2 · 3H2O
5.DA.45Hydrotalcite-2HMg6Al2(CO3)(OH)16 · 4H2O
5.DA.45ZaccagnaiteZn4Al2(OH)12[CO3] · 3H2O
5.DA.50ComblainiteNi4Co2(OH)12[CO3] · 3H2O
5.DA.50DesautelsiteMg6Mn23+(OH)16[CO3] · 4H2O
5.DA.50HydrotalciteMg6Al2(OH)16[CO3] · 4H2O
5.DA.50Pyroaurite-3RMg6Fe23+(OH)16[CO3] · 4H2O
5.DA.50ReevesiteNi6Fe23+(OH)16(CO3) · 4H2O
5.DA.50StichtiteMg6Cr2(OH)16[CO3] · 4H2O
5.DA.50TakoviteNi6Al2(OH)16[CO3] · 4H2O
5.DA.50UM1998-10-CO:CoHNiCo6Fe2(CO3)(OH)16 · 4H2O ?
5.DA.55CoalingiteMg10Fe23+(OH)24[CO3] · 2H2O
11.13.2Pyroaurite-3RMg6Fe23+(OH)16[CO3] · 4H2O
11.13.4BrugnatelliteMg6Fe3+(CO3)(OH)13 · 4H2O
11.13.5CoalingiteMg10Fe23+(OH)24[CO3] · 2H2O

Other Names for Pyroaurite-2H

Name in Other Languages:
Simplified Chinese:水碳铁镁石
Traditional Chinese:水碳鐵鎂石

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 Pyroaurite-2H

Reference List:
Aminoff and Broomé (1930), Svenska Vetenskapsakademien, Stockholm, Handlingar: 9: 3, no. 5: 23.

Frondel, C. (1941): Constitution and polymorphism of the pyroaurite and sjögrenite groups. American Mineralogist 26, 295-315.

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: 659-660.

Allmann, R. and H.-H. Lohse (1966): Die Kristallstruktur des Sjögrenits und eines Umwandlungsproduktes des Koenenits (= Chlor-Manasseits). Neues Jahrb. Mineral., Monatsh., 161–181.

Ingram, L. and H.F.W. Taylor (1967): The crystal structures of sjögrenite and pyroaurite. Mineral. Mag., 36, 465–479.

Zapiski Vserossiyskogo Mineralogicheskogo Obshchestva (1983): 112: 617.

Ivanov, O.K., Y.V. Mozzherin, and V.I. Vilisov (1986): New data on sjögrenite. Izvestiya Akad. Nauk Kazakh. SSR, Geol. Ser. 1, 40–45 (in Russian).

Mills, S.J., Christy, A.G., Genin, J.-M.R., Kameda, T., Colombo, F. (2012): Nomenclature of the hydrotalcite supergroup: natural layered double hydroxides. Mineralogical Magazine, 76, 1289-1336.

Internet Links for Pyroaurite-2H

Localities for Pyroaurite-2H

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.
  • Tasmania
    • Corinna-Savage River district
Bottrill & Taheri, 2008, Savage River mine, Unpub. Rept, Mineral Resources Tasmania
    • Huon district
      • Weld river
Bottrill & Baker (in prep) Catalogue of minerals of Tasmania
    • Trial Harbour district
Bottrill & Baker (in prep) Catalogue of minerals of Tasmania
    • Zeehan district
      • Mt Heemskirk mineral field
Bottrill & Baker (in prep) Catalogue of minerals of Tasmania
  • Lower Austria
    • Waldviertel
      • Persenbeug-Gottsdorf
        • Loja
Löffler, E. & Kolitsch, U. (2011): Die Mineralien der Loja bei Persenbeug, Niederösterreich (II). Mineralien-Welt. 22 (4): 51-62
  • Québec
    • Chaudière-Appalaches
      • Les Appalaches RCM
        • Saint-Julien
SABINA, A.P. (1967) Geological Survey of canada Paper, 66-51, 170p
  • Bavaria
    • Upper Palatinate
      • Winklarn
Wittern: "Mineralfundorte in Deutschland", 2001
  • Lower Saxony
    • Harz
      • Goslar
        • Grane Reservoir
Schnorrer-Köhler, G. (1991): Mineralogische Notizen V. Aufschluss 42, 155-171.
  • Sardinia
    • Cagliari Province
      • Teulada
Conti L, Cozupoli D., Lombardi G, Traversa g. 1970 - Segnalazione di Sjögrenite nelle contattiti presso Teulada (Sardegna meridionale) Per. Min. Roma, vol. 39 A, (special volume), pp. 119-127
  • Trentino-Alto Adige (Trentino-Südtirol)
    • Trento Province
      • Lagarina Valley
        • Mt. Baldo
          • Ala
            • Pilcante
Bortolozzi G., Boscardin M., Rocchetti I. and Bersani D. (2013): Cafetite e kassite della cava di Pilcante in Val d'Adige (Ala, Trento). Micro, Vol 11, 1, pagg.39-48.
  • Veneto
    • Vicenza Province
      • Astico Valley
        • Cogollo del Cengio
Boscardin M.,Daleffe A.,Rocchetti I., Zordan A. (2011) " Minerali del Vicentino - Aggiornamenti, località e nuove determinazioni " Museo di Archeologia e Scienze Naturali “G. Zannato” – Montecchio Maggiore (Vicenza), pp.183
      • Laghi
Antonio Zordan collection
      • Posina
        • Borcola Pass
Boscardin M.,Daleffe A.,Rocchetti I., Zordan A. (2011) " Minerali del Vicentino - Aggiornamenti, località e nuove determinazioni " Museo di Archeologia e Scienze Naturali “G. Zannato” – Montecchio Maggiore (Vicenza), pp.183
        • Pasubio Massif
          • Punta della Lucche
Boscardin M.,Daleffe A.,Rocchetti I., Zordan A. (2011) " Minerali del Vicentino - Aggiornamenti, località e nuove determinazioni " Museo di Archeologia e Scienze Naturali “G. Zannato” – Montecchio Maggiore (Vicenza), pp.183
  • Honshu Island
    • Chubu Region
      • Aichi prefecture
        • Shinshiro city
Alfredo Petrov - unpublished document - 2007
Yamada, S. (2004) Nihonsan-koubutsu Gojuon-hairetsu Sanchi-ichiranhyou (111 pp.)
  • Northern Kazakhstan Province (Soltüstik Qazaqstan Oblysy; Severo-Kazakhstanskaya Oblast')
    • Zlatogorsk
      • Zlatogorsk ultramafic intrusion
Pekov, I. (1998) Minerals First discovered on the territory of the former Soviet Union 369p. Ocean Pictures, Moscow
  • Eastern-Siberian Region
    • Prebaikalia (Pribaikal'e)
      • Irkutskaya Oblast'
        • Zheleznogorsk
Mazurov, M.P., Grishina, S.N., Istomin, V.E., and Titov, A.T. (2007): Geology of Ore Deposits 49(4), 271-284.; Mazurov et al (2007) Geology of Ore Deposits, 49, 271–284.
  • Northern Region
    • Murmanskaja Oblast'
      • Kola Peninsula
        • Kovdor Massif
Sweden (TL)
  • Värmland
    • Filipstad
Progr.Abstr.Min.Soc.Amer.(1940) p. 6; 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.
      • Persberg district
Sandström, F., Lorin, T. & Strand, U. (2009): Geologi och mineralogi i Gåsgruvefältet, Filipstad. Litofilen. 26 (2): 16-38
Linden, R.H. (2002): Gåsgruvan, En mineralundersökning under åren 1996-2002. Östra Värmlands Mineralsällskap (Cited in Sandström, F., Lorin, T. & Strand, U. (2009): Geologi och mineralogi i Gåsgruvefältet, Filipstad. Litofilen. 26 (2): 16-38
Östra Värmlands Mineral Society,Långban,Sweden
  • Scotland
    • Shetland Islands
      • Unst
        • Baltasound-Haroldswick area
Dr Stephen Moreton collection.
  • California
    • San Francisco Co.
      • San Francisco
Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 340; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 199.
    • Sonoma Co.
      • Healdsburg
Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 200.
  • New Jersey
    • Sussex Co.
      • Franklin Mining District
        • Ogdensburg
          • Sterling Hill
Dunn, P.J. & Leavens, Min.Rec.:12:371-372: (1981); Dunn(1995):Pt4:625.; Dunn, P. (1995) Franklin and Sterling Hill, privately published.
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