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yellowish-green to greenish-white
Specific Gravity:
3.062 (Calculated)
Crystal System:
Named for type locality, Eldfell volcano, Heimaey, Iceland
Isostructural with:
Yavapaiite Group. Chemically and structurally corresponds to the synthetic NaFe(SO4)2. The first anhydrous and hydrogen-free Na-Fe sulphate (compare the associated 'Unnamed (Na-Fe Sulphate)').

The Na analogue of Yavapaiite.
Water-sensitive and relatively unstable under ambient conditions.

Related to but not isostructural with markhininite.

Singh et al. (2015) report the mineral to be a potential cathode for the Na-ion batteries. Similar study is by Yu et al. (2016).

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Classification of EldfelliteHide

Approval Year:

7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
A : Sulfates (selenates, etc.) without additional anions, without H2O
C : With medium-sized and large cations

3 : AXO4

Physical Properties of EldfelliteHide

yellowish-green to greenish-white
{001} (basing on the structure analysis)
3.062 g/cm3 (Calculated)

Chemical Properties of EldfelliteHide

Common Impurities:

Crystallography of EldfelliteHide

Crystal System:
Class (H-M):
2/m - Prismatic
Space Group:
Cell Parameters:
a = 8.0 43(4) Å, b = 5.139(2) Å, c = 7.115(4) Å
β = 92.13(2)°
a:b:c = 1.557 : 1 : 1.385
Unit Cell V:
293.9 ų

X-Ray Powder DiffractionHide

Powder Diffraction Data:
3.73 (80)
3.64 (50)
3.43 (50)
2.77 (100)
2.72 (60)
2.57 (30)
2.370 (60)
1.650 (30)

Type Occurrence of EldfelliteHide

General Appearance of Type Material:
soft, fragile aggregates (along with opal and tamarugite) of thin platy ({001}) crystals, up to 0.02 mm; may be rosette-forming
Place of Conservation of Type Material:
Icelandic Institute of Natural History, Reykjavík, Iceland (registration no.: NI 13556)
Geological Setting of Type Material:
fumarolic encrustations close to the surface
Associated Minerals at Type Locality:

Synonyms of EldfelliteHide

Relationship of Eldfellite to other SpeciesHide

Other Members of this group:
YavapaiiteKFe(SO4)2Mon. 2/m : B2/m

Related Minerals - Nickel-Strunz GroupingHide

7.AC.Aluminopyracmonite(NH4)3Al(SO4)3Trig. 3 : R3
7.AC.Acmonidesite(NH4,K,Pb)8NaFe2+4(SO4)5Cl8Orth. 2 2 2 : C2 2 21
7.AC.05VanthoffiteNa6Mg(SO4)4Mon. 2/m : P21/b
7.AC.08Pyracmonite(NH4)3Fe(SO4)3Trig. 3m : R3c
7.AC.10LangbeiniteK2Mg2(SO4)3Iso. 2 3 : P21 3
7.AC.10ManganolangbeiniteK2Mn2(SO4)3Iso. 2 3 : P21 3
7.AC.15YavapaiiteKFe(SO4)2Mon. 2/m : B2/m
7.AC.20Godovikovite(NH4)Al(SO4)2Trig. 3 2 : P3 2 1
7.AC.20Sabieite(NH4)Fe3+(SO4)2Trig. 3 2 : P3 2 1
7.AC.25ThénarditeNa2SO4Orth. mmm (2/m 2/m 2/m) : Fddd
7.AC.30MetathénarditeNa2SO4Hex. 6/mmm (6/m 2/m 2/m) : P63/mmc

Related Minerals - Dana Grouping (8th Ed.)Hide 2/m : B2/m

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 EldfelliteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Stoiber, R.E., Rose, W.I., Jr. (1969) Recent volcanic and fumarolic activity at Santiaguito volcano, Guatemala. Bulletin of Volcanology: 33: 475-502.
Giester, G. (1993) Crystal structure of the yavapaiite type compound NaFe[SeO4]2. Mineralogy and Petrology: 48: 227-233.
Jakobsson, S.P., Leonardsen, E.S., Balic-Zunic, T., Jónsson, S.S. (2008) Encrustations from three recent volcanic eruptions in Iceland: The 1963-1967 Surtsey, the 1973 Eldfell and the 1991 Hekla eruptions. Fjölrit Náttúrufrædistofnunar: 52: 5-67.
Balic-Zunic, T., Garavelli, A., Acquafredda, P., Leonardsen, E., Jakobsson, S.P. (2009) Eldfellite, a new fumarolic mineral from Eldfell volcano, Iceland. Mineralogical Magazine: 73: 51-57.
Piilonen, P.C., Poirier, G. (2010) New mineral names. American Mineralogist: 95: 204-208.
Singh, P., Shiva, K., Celio, H., Goodenough, J.B. (2015) Eldfellite, NaFe(SO4)2: an intercalation cathode host for low-cost Na-ion batteries. Energy and Environmental Science: 8: 3000-3005.
Anthony, J.W., Bideaux, R.A., Bladh, K.W., Nichols, M.C., Eds. Handbook of Mineralogy, Mineralogical Society of America, Chantilly, VA 20151-1110, USA. http://www.handbookofmineralogy.org/ (2016)
Yu, C.-J., Choe, S.-H., Ri, G.-C., Jong, U.-G., Hong, S.-N. (2016) First-principles Study of Crystal Structure and electronic properties of SIB cathode material - NaFe(SO4)2. arXiv:1605.04947 [cond-mat.mtrl-sci]

Internet Links for EldfelliteHide

Localities for EldfelliteHide

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.
  • Quetzaltenango Department
    • El Palmar
Stoiber, R.E. & Rose, W.I., Jr. (1969): Recent volcanic and fumarolic activity at Santiaguito volcano, Guatemala. Bulletin of Volcanology, 33, 475-502.
Iceland (TL)
  • Southern Region
    • Vestmannaeyjar archipelago (Westman islands)
      • Heimaey island
Balić-Žunić, T., Garavelli, A., Acquafredda, P., Leonardsen, E., & Jakobsson, S. P. (2009). Eldfellite, NaFe (SO4) 2, a new fumarolic mineral from Eldfell volcano, Iceland. Mineralogical Magazine, 73(1), 51-57.
Mineral and/or Locality  
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