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Edward Henry Kraus
KFe(SO4)2 · H2O
Pale lemon yellow, ...
Sub-Vitreous, Waxy, Earthy
Named by William F. Foshag in honor of Dr. Edward Henry Kraus [December 1, 1875 Syracuse, New York, USA - February 3, 1973 Ann Arbor, Michigan, USA], American mineralogist, University of Michigan.
This page provides mineralogical data about Krausite.

Classification of Krausite

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

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

5 : AB(XO4)2·xH2O

25 : Sulphates
11 : Sulphates of Fe and other metals

Physical Properties of Krausite

Sub-Vitreous, Waxy, Earthy
Diaphaneity (Transparency):
Transparent, Translucent
Not vitreous
Pale lemon yellow, yellowish green, gray; colourless to pale yellow in transmitted light.
Hardness (Mohs):
Perfect on {001}; Good on {100}
2.84 g/cm3 (Measured)    2.839 g/cm3 (Calculated)

Optical Data of Krausite

Biaxial (+)
RI values:
nα = 1.588 nβ = 1.650 nγ = 1.722
Measured: 75°
Max Birefringence:
δ = 0.134
Image shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:
relatively strong
Optical Extinction:
Z=b, Y^c = -35°
X = Colourless
Y = Pale yellow
Z = Pale yellow
2V large

Chemical Properties of Krausite

KFe(SO4)2 · H2O
IMA Formula:
KFe3+(SO4)2 · H2O
Elements listed in formula:
Analytical Data:
Slowly decomposed by water. Yields acid water.

Crystallography of Krausite

Crystal System:
Class (H-M):
2/m - Prismatic
Space Group:
Space Group Setting:
Cell Parameters:
a = 7.91 Å, b = 5.15 Å, c = 8.99 Å
β = 102.75°
a:b:c = 1.536 : 1 : 1.746
Unit Cell Volume:
V 357.19 ų (Calculated from Unit Cell)
Commonly earthy to finely granular. Crystals may be short prismatic [001]; also equant to tabular {001}. Larger crystals tend to be rough and opaque, smaller ones brilliant and clear.
X-Ray Powder Diffraction Data:
6.69 (70)
4.40 (80)
4.26 (50)
3.69 (70)
3.09 (100)
2.77 (40)
2.58 (40)
2.55 (40)
ICDD 18-1028

Occurrences of Krausite

Type Occurrence of Krausite

Place of Conservation of Type Material:
Smithsonian Institution, Washington DC
Geological Setting of Type Material:
Secondary mineral in sulfate bearing chert.
Empirical Formula:
KFe3+(SO4)2 · H2O
Associated Minerals at Type Locality:

Relationship of Krausite to other Species

7.CC.10TamarugiteNaAl(SO4)2 · 6H2O
7.CC.15KaliniteKAl(SO4)2 · 11H2O Not confirmed
7.CC.15MendoziteNaAl(SO4)2 · 11H2O
7.CC.20Lonecreekite(NH4)Fe3+(SO4)2 · 12H2O
7.CC.20Alum-(K)KAl(SO4)2 · 12H2O
7.CC.20Alum-(Na)NaAl(SO4)2 · 12H2O
7.CC.20Tschermigite(NH4)Al(SO4)2 · 12H2O
7.CC.20LanmuchangiteTl+Al(SO4)2 · 12H2O
7.CC.25VoltaiteK2Fe52+Fe33+Al(SO4)12 · 18H2O
7.CC.25ZincovoltaiteK2Zn5Fe33+Al(SO4)12 · 18H2O
7.CC.25PertlikiteK2(Fe2+,Mg)2Mg4Fe23+Al(SO4)12 · 18H2O
7.CC.25Ammoniomagnesiovoltaite(NH4)2Mg52+Fe33+Al(SO4)12 · 18H2O
7.CC.30KröhnkiteNa2Cu(SO4)2 · 2H2O
7.CC.35FerrinatriteNa3Fe(SO4)3 · 3H2O
7.CC.40GoldichiteKFe(SO4)2 · 4H2O
7.CC.45LöweiteNa12Mg7(SO4)13 · 15H2O
7.CC.50BlöditeNa2Mg(SO4)2 · 4H2O
7.CC.50NickelblöditeNa2(Ni,Mg)(SO4)2 · 4H2O
7.CC.50ChangoiteNa2Zn(SO4)2 · 4H2O
7.CC.50ZincblöditeNa2Zn(SO4)2 · 4H2O
7.CC.55LeoniteK2Mg(SO4)2 · 4H2O
7.CC.55MereiteriteK2Fe(SO4)2 · 4H2O
7.CC.60Boussingaultite(NH4)2Mg(SO4)2 · 6H2O
7.CC.60CyanochroiteK2Cu(SO4)2 · 6H2O
7.CC.60Mohrite(NH4)2Fe(SO4)2 · 6H2O
7.CC.60Nickelboussingaultite(NH4)2Ni(SO4)2 · 6H2O
7.CC.60PicromeriteK2Mg(SO4)2 · 6H2O
7.CC.65PolyhaliteK2Ca2Mg(SO4)4 · 2H2O
7.CC.70LeightoniteK2Ca2Cu(SO4)4 · 2H2O
7.CC.75AmarilliteNaFe(SO4)2 · 6H2O
7.CC.80KonyaiteNa2Mg(SO4)2 · 5H2O
7.CC.85WattevilleiteNa2Ca(SO4)2 · 4H2O (?)
25.11.2SideronatriteNa2Fe(SO4)2(OH) · 3H2O
25.11.3MetasideronatriteNa2Fe(SO4)2(OH) · H2O
25.11.4FerrinatriteNa3Fe(SO4)3 · 3H2O
25.11.5AmarilliteNaFe(SO4)2 · 6H2O
25.11.8GoldichiteKFe(SO4)2 · 4H2O
25.11.9JarositeKFe3+ 3(SO4)2(OH)6
25.11.10VoltaiteK2Fe52+Fe33+Al(SO4)12 · 18H2O
25.11.11UngemachiteK3Na8Fe(SO4)6(NO3)2 · 6H2O
25.11.12MetavoltineNa6K2FeFe6(SO4)12O2 · 18H2O
25.11.15Clairite(NH4)2Fe3(SO4)4(OH)3 · 3H2O
25.11.16Mohrite(NH4)2Fe(SO4)2 · 6H2O
25.11.17Lonecreekite(NH4)Fe3+(SO4)2 · 12H2O
25.11.19BotryogenMgFe3+(SO4)2(OH) · 7H2O
25.11.21Slavíkite(H3O+)3Mg6Fe15(SO4)21(OH)18 · 98H2O
25.11.23SturmaniteCa6(Fe3+,Al,Mn3+)2(SO4)2[B(OH)4](OH)12 · 25H2O
25.11.25AluminocopiapiteAl2/3Fe43+(SO4)6(OH)2 · 20H2O
25.11.26HalotrichiteFeAl2(SO4)4 · 22H2O
25.11.27Idrizite(Mg,Fe)(Al,Fe)2(SO4)3(OH)2 · 15H2O or near
25.11.28LishizheniteZnFe2(SO4)4 · 14H2O
25.11.29ZincovoltaiteK2Zn5Fe33+Al(SO4)12 · 18H2O

Other Names for Krausite

Name in Other Languages:
Simplified Chinese:钾铁矾

Other Information

Other Information:
Slowly decomposed by water leaving ferric oxide.
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 Krausite

Reference List:
Foshag, W.F. (1931): Krausite, a new sulphate from California. American Mineralogist: 16: 352-360.

Graeber, E.J. & A. Rosenzweig (1965): The unit cell of Krausite. American Mineralogist: 50: 504-507.

Graeber, E.J., B. Morosin & A. Rosenzweig (1965): The crystal structure of Krausite, KFe(SO4)2•H2O: American Mineralogist: 50: 1929-1936.

American Mineralogist (1986): 71: 202-205.

Internet Links for Krausite URL:
Please feel free to link to this page.

Localities for Krausite

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.
(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.
  • Jujuy
    • Santa Bárbara Department
      • Cerros de Santa Bárbara (Cerro Santa Bárbara)
        • El Palmar hot springs; Marquez-Zavalia, Maria Florencia, Lomniczi de Upton, Irene & Galliski, Miguel Angel (2001): Krausite in fumaroles from Santa Barbara mine, northwestern Argentina. Neues Jahrbuch für Mineralogie, Monatshefte 2001, 378-384. ; Zavalia, Maria Florencia Marquez & Galliski, Miguel Angel (1995): Goldichite of fumarolic origin from the Santa Barbara mine, Jujuy, northwestern Argentina. Canadian Mineralogist 33, 1059-1062.
  • Antofagasta Region
    • El Loa Province
      • Calama
        • Cerritos Bayos
Samples analysed by Dr. Jochen Schluter, Curator of Hamburg Mineralogical Museum, Germany; Kampf, A.R.; Mills, S.J.; Housley, R.M.; Williams, P.A.; Dini, M. (2012): Alcaparrosaite, K3Ti4+Fe3+(SO4)4O(H2O)2, a new hydrophobic Ti4+ sulfate from Alcaparrosa, Chile. Mineralogical Magazine 76, 851-861.
        • Chuquicamata District
          • Toki Cu deposit (Toki Cluster)
Natural History Museum Vienna collection (Uwe Kolitsch SXRD on Arturo Molina material)
  • Xinjiang Autonomous Region
    • Hami Prefecture (Kumul Prefecture; Qumul Prefecture)
      • Hami Co. (Kumul Co.; Qumul Co.)
Xu Ying-xia, Ding Kui-shou, Qin Ke-zhang, Miao Yu, Fang Tong-hui, Xu Xing-wang, and Sun He (2006): Geology in China 33(3), 605-616.
  • Occitanie
    • Gard
      • Saint-Laurent-le-Minier
Minéralogie de la mine des malines (Daniel Gol, Alain Martaud, Nicolas Meisser, Pascal Chollet) - Le regne minéral, H.S. XVI, pp 49-86.
- Gol, D, Martaud, A., Meisser, N. & Chollet, P. (2010): Minéralogie des Malines, Gard. Le Règne Minéral, HS XVI, 49-88.
  • Saxony
    • Dresden
Thalheim, K.; Reichel, W. & Witzke, T. (1991): Die Minerale des Döhlener Beckens.- Schriften des Staatlichen Museums für Mineralogie und Geologie zu Dresden, Nr. 3
  • Attikí Prefecture (Attica; Attika)
    • Lavrion District (Laurion; Laurium)
      • Lavrion District Mines
        • Plaka
          • Plaka Mines
Dr. A. Godelitsas collection and analysis; Kolitsch, U., Rieck, B., Brandstätter, F., Schreiber, F., Fabritz, K. H., Blaß, G. & Gröbner, J. (2014): Neufunde aus dem altem Bergbau und den Schlacken von Lavrion (I). Mineralien-Welt 25 (1), 60-75 (in German).
Branko Rieck Collection
        • Sounion area
Branko Rieck Collection
  • Campania
    • Phlegrean Volcanic Complex
      • Naples Province
          • Pozzuoli
De Michele, V. (1974). Guida mineralogica d'Italia. Istituto Geografico De Agostini, Novara, 2 vol
  • Sicily
    • Messina Province
      • Eolie Islands (Aeolian Islands)
        • Lipari
          • Vulcano Island
            • Porto Levante
              • Faraglioni di Levante (Grotte dei Faraglioni; Grotte del Faraglione; "Grotte de Faraglione")
                • Faraglione Nico (Faraglione Piccolo; Faragghiune Nicu)
Campostrini I. et al - Vulcano: ein aussergewohnlicher Fundpunkt von neuen und seltenen Mineralien - MineralienWelt 2010 - nr.3 - p.40-57
  • Durango
    • Mun. de Cuencamé
      • Velardeña District
        • Velardeña
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: 463; Handbook of Mineralogy - Anthony, Bideaux, Bladh, Nichols.; Am Min (1931), 16:352-360
  • Ayacucho Department
    • Lucanas Province
      • Huac-huas (Huacuas)
Hyršl, J. (2010): Ein Neufund fantastischer Sulfate in der Mina Javier. Mineralien-Welt 21 (3), 68-71 (in German). ; Roth, P. and Meisser, N. (2012) Goldichit: Ausgezeichnete Kristalle aur Peru. Lapis, 37, #5, 37.; Frost, R. L., Gobac, Ž. Ž., López, A., Xi, Y., Scholz, R., Lana, C., & Lima, R. M. F. (2014). Characterization of the sulphate mineral coquimbite, a secondary iron sulphate from Javier Ortega mine, Lucanas Province, Peru–Using infrared, Raman spectroscopy and thermogravimetry. Journal of Molecular Structure, 1063, 251-258.
  • California
    • San Bernardino Co.
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: 616.
        • Calico District (Daggett District; Calico-Daggett area)
          • Calico
Foshag, William Frederick (1931c), Krausite, a new sulphate from California: American Mineralogist: 16: 352-360; Moller, W.P. (1963) Sulfur Hole. Mineralogist: 31, part 1, N. 3: 14-15; part 2, No. 4: 12, 13; Graeber, E.J. and Rosenzweig, A. (1965) The unit cell of krausite. American Mineralogist: 50: 504-507; Graeber, E.J., Morosin, B., and Rosenzweig, A. (1965) The crystal structure of krausite, KFe(SO4)2 •H2O. American Mineralogist: 50: 1929-1936; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 265, 273, 278; Joseph F. Cooper, Jr., Gail E. Dunning, Ted A. Hadley, and William P. Moller (2001) The Sulfur Hole, Calico District, San Bernardino County, California
  • Utah
    • Emery Co.
      • San Rafael District (San Rafael Swell)
        • Calf Mesa
In the collection of Brent Thorne
    • Wayne Co.
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