Alunite
A valid IMA mineral species - grandfathered
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About Alunite
Formula:
KAl3(SO4)2(OH)6
Colour:
white, pale shades of gray, yellow, red, to reddish brown
Lustre:
Vitreous, Pearly
Hardness:
3½ - 4
Specific Gravity:
2.6 - 2.9
Crystal System:
Trigonal
Member of:
Name:
Named from the Latin for alum.
Common member of the alunite supergroup.
The Al analogue of jarosite and the K analogue of natroalunite.
Alunite has been used for dating (K-Ar method) of weathering processes in ore deposits or of the deposition of alunite in caves.
Alunite was also detected on Mars (Ehlmann et al., 2016; Ranalli and Swayze, 2024).
The Al analogue of jarosite and the K analogue of natroalunite.
Alunite has been used for dating (K-Ar method) of weathering processes in ore deposits or of the deposition of alunite in caves.
Alunite was also detected on Mars (Ehlmann et al., 2016; Ranalli and Swayze, 2024).
Unique Identifiers
Mindat ID:
161
Long-form identifier:
mindat:1:1:161:6
Similar Names
| Allanit | A synonym of 'Allanite' | |
| Allanite | A synonym of Allanite Group | |
| Allanite-(Ce) | A valid IMA mineral species - grandfathered | (CaCe)(AlAlFe2+)O[Si2O7][SiO4](OH) |
| Allanite-(La) | A valid IMA mineral species | (CaLa)(AlAlFe2+)O[Si2O7][SiO4](OH) |
| Allanite-(Nd) | A valid IMA mineral species | (CaNd)(AlAlFe2+)O[Si2O7][SiO4](OH) |
| Allanite-(Sm) | A valid IMA mineral species | (CaSm)(AlAlFe2+)O[Si2O7][SiO4](OH) |
| Allanite-(Y) | A valid IMA mineral species - grandfathered | (CaY)(AlAlFe2+)O[Si2O7][SiO4](OH) |
| Allanitt-(Y) | A synonym | |
| Allenite | A synonym of Pentahydrite | |
| Alnöite | A synonym of 'Lamprophyric-pyroxene-calcite-biotite olivine-melilitite' | |
| Alusite | A synonym of 'Alushtite' | |
| Falunite | A synonym of 'Fahlunite' | |
| Olenite | A valid IMA mineral species | NaAl3Al6(Si6O18)(BO3)3O3(OH) |
| Ollenite | A rock subtype |
IMA Classification of Alunite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
KAl3(S6+O4)2(OH)6
Classification of Alunite
7.BC.10
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
B : Sulfates (selenates, etc.) with additional anions, without H2O
C : With medium-sized and large cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
B : Sulfates (selenates, etc.) with additional anions, without H2O
C : With medium-sized and large cations
30.2.4.1
30 : ANHYDROUS SULFATES CONTAINING HYDROXYL OR HALOGEN
2 : (AB)2(XO4)Zq
30 : ANHYDROUS SULFATES CONTAINING HYDROXYL OR HALOGEN
2 : (AB)2(XO4)Zq
25.6.18
25 : Sulphates
6 : Sulphates of Al and Tl
25 : Sulphates
6 : Sulphates of Al and Tl
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Alu | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Alu | Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371 |
| Aln | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Pronunciation of Alunite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Alunite
Vitreous, Pearly
Transparency:
Transparent, Translucent
Comment:
Somewhat pearly on {0001}.
Colour:
White, pale shades of gray, yellow, red, to reddish brown
Comment:
Colorless if pure
Streak:
White
Hardness:
3½ - 4 on Mohs scale
Hardness Data:
Measured
Tenacity:
Brittle
Cleavage:
Distinct/Good
On {0001}, distinct; on {0112}, traces. Handbook of mineralogy: On {0001}, perfect
On {0001}, distinct; on {0112}, traces. Handbook of mineralogy: On {0001}, perfect
Fracture:
Irregular/Uneven, Splintery, Conchoidal
Density:
2.6 - 2.9 g/cm3 (Measured) 2.82 g/cm3 (Calculated)
Comment:
Values on massive material.
Optical Data of Alunite
Type:
Uniaxial (+)
RI values:
nω = 1.572 nε = 1.592
Max. Birefringence:
δ = 0.020
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Moderate (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Chemistry of Alunite
Mindat Formula:
KAl3(SO4)2(OH)6
Element Weights:
Common Impurities:
Na,Fe
Age distribution
Recorded ages:
Cenozoic : 18.9 ± 5.6 Ma to 1.17 ± 0.16 Ma - based on 34 recorded ages.
Sample ages:
| Sample ID | Recorded age | Geologic Time | Dating method |
|---|---|---|---|
| 1 | 1.17 ± 0.16 Ma | Pleistocene | K-Ar |
| 2 | 1.35 ± 0.1 Ma | Pleistocene | K-Ar |
| 3 | 1.39 ± 0.06 Ma | Pleistocene | K-Ar |
| 4 | 1.44 ± 0.08 Ma | Pleistocene | K-Ar |
| 5 | 1.56 ± 0.29 Ma | Pleistocene | K-Ar |
| 6 | 7.18 ± 0.15 Ma | Miocene | 40Ar/39Ar |
| 7 | 7.25 ± 0.14 Ma | Miocene | 40Ar/39Ar |
| 8 | 7.38 ± 2.88 Ma | Miocene | 40Ar/39Ar |
| 9 | 8.15 ± 12.78 Ma | Miocene | 40Ar/39Ar |
| 10 | 8.61 ± 0.45 Ma | Miocene | 40Ar/39Ar |
| 11 | 8.63 ± 0.41 Ma | Miocene | 40Ar/39Ar |
| 12 | 8.71 ± 0.21 Ma | Miocene | 40Ar/39Ar |
| 13 | 8.86 ± 0.38 Ma | Miocene | 40Ar/39Ar |
| 14 | 9.5 ± 5.3 Ma | Miocene | K-Ar |
| 15 | 10.1 ± 0.6 Ma | Miocene | K-Ar |
| 16 | 10.42 ± 0.28 Ma | Miocene | 40Ar/39Ar |
| 17 | 11.00 ± 0.27 Ma | Miocene | 40Ar/39Ar |
| 18 | 11.5 ± 3.5 Ma | Miocene | K-Ar |
| 19 | 13 Ma | Miocene | K-Ar |
| 20 | 18.9 ± 5.6 Ma | Miocene | K-Ar |
Sample references:
Crystallography of Alunite
Crystal System:
Trigonal
Class (H-M):
3m - Ditrigonal Pyramidal
Space Group:
R3m
Cell Parameters:
a = 6.98 Å, c = 17.32 Å
Ratio:
a:c = 1 : 2.481
Unit Cell V:
730.78 ų (Calculated from Unit Cell)
Morphology:
Rarely in small crystals; as druses in massive material or as aggregates. Crystals tabular {0001} or terminated by flat vicinal rhombohedra; rhombohedral and commonly pseudo-cubic {0112}. Lenticular based on distortion or vicinal development. Massive, granular to dense. As rocky, admixed masses.
Crystallographic forms of Alunite
Crystal Atlas:
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Alunite no.1 - {102} - Goldschmidt (1913-1926)
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0018984 | Alunite | Zema M, Callegari A M, Tarantino S C, Gasparini E, Ghigna P (2012) Thermal expansion of alunite up to dehydroxylation and collapse of the crystal structure Mineralogical Magazine 76 613-623 | 2012 | Hungary | 0 | 298 | |
| 0015817 | Alunite | Schukow H, Breitinger D K, Zeiske T, Kubanek F, Mohr J, Schwab R G (1999) Localization of hydrogen and content of oxonium cations in alunite via neutron diffraction Zeitschrift fur Anorganische und Allgemeine Chemie 625 1047-1050 | 1999 | synthetic | 0 | 293 | |
| 0014755 | Alunite | Menchetti S, Sabelli C (1976) Crystal chemistry of the alunite series: crystal structure refinement of alunite and synthetic jarosite Neues Jahrbuch fur Mineralogie, Monatshefte 1976 406-417 | 1976 | Montioni, Toscana, Italy | 0 | 293 | |
| 0018985 | Alunite | Zema M, Callegari A M, Tarantino S C, Gasparini E, Ghigna P (2012) Thermal expansion of alunite up to dehydroxylation and collapse of the crystal structure Mineralogical Magazine 76 613-623 | 2012 | Hungary | 0 | 373 | |
| 0018986 | Alunite | Zema M, Callegari A M, Tarantino S C, Gasparini E, Ghigna P (2012) Thermal expansion of alunite up to dehydroxylation and collapse of the crystal structure Mineralogical Magazine 76 613-623 | 2012 | Hungary | 0 | 473 | |
| 0018987 | Alunite | Zema M, Callegari A M, Tarantino S C, Gasparini E, Ghigna P (2012) Thermal expansion of alunite up to dehydroxylation and collapse of the crystal structure Mineralogical Magazine 76 613-623 | 2012 | Hungary | 0 | 573 | |
| 0018988 | Alunite | Zema M, Callegari A M, Tarantino S C, Gasparini E, Ghigna P (2012) Thermal expansion of alunite up to dehydroxylation and collapse of the crystal structure Mineralogical Magazine 76 613-623 | 2012 | Hungary | 0 | 673 | |
| 0018989 | Alunite | Zema M, Callegari A M, Tarantino S C, Gasparini E, Ghigna P (2012) Thermal expansion of alunite up to dehydroxylation and collapse of the crystal structure Mineralogical Magazine 76 613-623 | 2012 | Hungary | 0 | 723 | |
| 0018990 | Alunite | Zema M, Callegari A M, Tarantino S C, Gasparini E, Ghigna P (2012) Thermal expansion of alunite up to dehydroxylation and collapse of the crystal structure Mineralogical Magazine 76 613-623 | 2012 | Hungary | 0 | 773 | |
| 0009047 | Alunite | Majzlan J, Speziale S, Duffy T S, Burns P C (2006) Single-crystal elastic properties of alunite, KAl3(SO4)2(OH)6 Physics and Chemistry of Minerals 33 567-573 | 2006 | 0 | 293 | ||
| 0000037 | Alunite | Pabst A (1947) Some computations on svanbergite, woodhouseite and alunite American Mineralogist 32 16-30 |  | 1947 | 0 | 293 | |
| 0000016 | Alunite | Hendricks S B (1937) The crystal structures of alunite and the jarosites American Mineralogist 22 773-784 | | 1937 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.948 Å | (53) |
| 2.984 Å | (100) |
| 2.884 Å | (106) |
| 2.291 Å | (81) |
| 1.502 Å | (36) |
Comments:
Marysvale, Utah, USA. The data are from Parker (1954).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 45a : [Sulfates, arsenates, selenates, antimonates] | |
| 46 : Near-surface hydrothermal alteration of minerals (see also #22) | |
| 47a : [Near-surface hydration of prior minerals] | |
| 47b : [Sulfates and sulfites] | |
| 47i : [Terrestrial weathering of meteorites] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Geological Setting:
Formed between 15°C and 400°C by the action of sulfate, which may be generated from pyrite or solfataric action, on aluminous rocks, commonly accompanied by kaolinitization and silicification.
Type Occurrence of Alunite
Synonyms of Alunite
Other Language Names for Alunite
Dutch:Aluniet
German:Alunit
Alaun-Grammit
Alaunspat
Alaunstein (of Werner)
Aluminilit
Kalioalunit
K-Alunit
Lœvigit
Lœwigit
Lowigit
Alaun-Grammit
Alaunspat
Alaunstein (of Werner)
Aluminilit
Kalioalunit
K-Alunit
Lœvigit
Lœwigit
Lowigit
Latin:Alumen de Tolpha
Norwegian:Alunitt
Russian:Алунит
Simplified Chinese:明矾石
Swedish:Romersk Alunsten
Relationship of Alunite to other Species
Member of:
Other Members of Alunite Group:
| Ammonioalunite | (NH4)Al3(SO4)2(OH)6 | Trig. |
| Ammoniojarosite | (NH4)Fe3+3(SO4)2(OH)6 | Trig. 3m : R3m |
| Argentojarosite | AgFe3+3(SO4)2(OH)6 | Trig. 3m : R3m |
| Beaverite-(Cu) | Pb(Fe3+2Cu)(SO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Beaverite-(Zn) | Pb(Fe3+2Zn)(SO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Dorallcharite | TlFe3+3(SO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Huangite | Ca0.5Al3(SO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Hydroniumjarosite | (H3O)Fe3+3(SO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Jarosite | KFe3+3(SO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Natroalunite | NaAl3(SO4)2(OH)6 | Trig. 3m : R3m |
| 'Natroalunite-2c' | (Na,Ca0.5,K)Al3(SO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Natrojarosite | NaFe3(SO4)2(OH)6 | Trig. 3m : R3m |
| Osarizawaite | Pb(Al2Cu2+)(SO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Plumbojarosite | Pb0.5Fe3+3(SO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Schlossmacherite | (H3O)Al3(SO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Walthierite | Ba0.5Al3(SO4)2(OH)6 | Trig. |
Forms a series with:
Common Associates
Associations Based on Photo Data:
| 76 photos of Alunite associated with Native Gold | Au |
| 60 photos of Alunite associated with Famatinite | Cu3SbS4 |
| 40 photos of Alunite associated with Rodalquilarite | Fe2(TeO2OH)3(TeO3)Cl |
| 37 photos of Alunite associated with Bismuthinite | Bi2S3 |
| 23 photos of Alunite associated with Pyrite | FeS2 |
| 17 photos of Alunite associated with 'Andorite' | AgPbSb3S6 |
| 17 photos of Alunite associated with Jamesonite | Pb4FeSb6S14 |
| 15 photos of Alunite associated with Cassiterite | SnO2 |
| 13 photos of Alunite associated with Quartz | SiO2 |
| 7 photos of Alunite associated with Jarosite | KFe3+3(SO4)2(OH)6 |
Related Minerals - Strunz-mindat Grouping
| 7.BC. | Viskontite | Pb5Cu2(SO4)3(SeO3)(OH)6 |
| 7.BC. | Zincochenite | Pb4Zn(OH)6(SO4)2 |
| 7.BC. | D'Ansite-(Mn) | Na21Mn2+(SO4)10Cl3 |
| 7.BC. | D'Ansite-(Fe) | Na21Fe2+(SO4)10Cl3 |
| 7.BC. | Acmonidesite | (NH4,K,Pb)8NaFe2+4(SO4)5Cl8 |
| 7.BC. | Adranosite | (NH4)4NaAl2(SO4)4Cl(OH)2 |
| 7.BC. | Chromviskontite | Pb5Cu2(CrO4)3(SeO3)(OH)6 |
| 7.BC. | Backite | Pb2AlTeO6Cl |
| 7.BC. | Adranosite-(Fe) | (NH4)4NaFe3+2(SO4)4Cl(OH)2 |
| 7.BC. | Agaite | Pb3CuTeO5(OH)2(CO3) |
| 7.BC. | Wildcatite | CaFe3+Te6+O5(OH) |
| 7.BC. | Hagstromite | Pb8Cu2+(Te6+O6)2(CO3)Cl4 |
| 7.BC.05 | D'Ansite | Na21Mg(SO4)10Cl3 |
| 7.BC.07 | 'Apatelite' | Fe3(SO4)2(OH)5 · 0.5H2O |
| 7.BC.07 | 'Unnamed (Ba-Fe Vanadate)' | Ba, Fe, V, O, H |
| 7.BC.10 | Jarosite | KFe3+3(SO4)2(OH)6 |
| 7.BC.10 | Dorallcharite | TlFe3+3(SO4)2(OH)6 |
| 7.BC.10 | Argentojarosite | AgFe3+3(SO4)2(OH)6 |
| 7.BC.10 | Natroalunite | NaAl3(SO4)2(OH)6 |
| 7.BC.10 | Natrojarosite | NaFe3(SO4)2(OH)6 |
| 7.BC.10 | Beaverite-(Cu) | Pb(Fe3+2Cu)(SO4)2(OH)6 |
| 7.BC.10 | Beaverite-(Zn) | Pb(Fe3+2Zn)(SO4)2(OH)6 |
| 7.BC.10 | Walthierite | Ba0.5Al3(SO4)2(OH)6 |
| 7.BC.10 | Huangite | Ca0.5Al3(SO4)2(OH)6 |
| 7.BC.10 | 'Natroalunite-2c' | (Na,Ca0.5,K)Al3(SO4)2(OH)6 |
| 7.BC.10 | Plumbojarosite | Pb0.5Fe3+3(SO4)2(OH)6 |
| 7.BC.10 | Karlseifertite | Pb(Ga2Ge)(AsO4)2(OH)6 |
| 7.BC.10 | Hydroniumjarosite | (H3O)Fe3+3(SO4)2(OH)6 |
| 7.BC.10 | Ammonioalunite | (NH4)Al3(SO4)2(OH)6 |
| 7.BC.10 | Ammoniojarosite | (NH4)Fe3+3(SO4)2(OH)6 |
| 7.BC.10 | Osarizawaite | Pb(Al2Cu2+)(SO4)2(OH)6 |
| 7.BC.10 | Schlossmacherite | (H3O)Al3(SO4)2(OH)6 |
| 7.BC.15 | Ye'elimite | Ca4Al6(SO4)O12 |
| 7.BC.20 | Nabokoite | KCu7(SO4)5(Te4+O3)OCl |
| 7.BC.20 | Puninite | Na2Cu3O(SO4)3 |
| 7.BC.20 | Atlasovite | K(BiO)Cu6Fe3+(SO4)5O3Cl |
| 7.BC.25 | Chlorothionite | K2Cu(SO4)Cl2 |
| 7.BC.30 | Euchlorine | KNaCu3(SO4)3O |
| 7.BC.30 | Fedotovite | K2Cu3(SO4)3O |
| 7.BC.35 | Kamchatkite | KCu3(SO4)2OCl |
| 7.BC.40 | Piypite | K4Cu4O2(SO4)4 · (Na,Cu)Cl |
| 7.BC.45 | Alumoklyuchevskite | K3Cu3(Al,Fe3+)(SO4)4O2 |
| 7.BC.45 | Belousovite | KZn(SO4)Cl |
| 7.BC.45 | Klyuchevskite | K3Cu3(Fe3+,Al)(SO4)4O2 |
| 7.BC.47 | Müllerite | Pb2Fe3+(Te6+O6)Cl |
| 7.BC.50 | Caledonite | Pb5Cu2(SO4)3(CO3)(OH)6 |
| 7.BC.50 | Elasmochloite | Na3Cu6BiO4(SO4)5 |
| 7.BC.52 | Eleomelanite | (K2Pb)Cu4O2(SO4)4 |
| 7.BC.55 | Falgarite | K4(VO)3(SO4)5 |
| 7.BC.55 | Wherryite | Pb7Cu2(SO4)4(SiO4)2(OH)2 |
| 7.BC.57 | Krasheninnikovite | KNa2CaMg(SO4)3F |
| 7.BC.60 | Wulffite | K3NaCu4O2(SO4)4 |
| 7.BC.60 | Parawulffite | K5Na3Cu8O4(SO4)8 |
| 7.BC.60 | Mammothite | Pb6Cu4AlSb5+O2(OH)16Cl4(SO4)2 |
| 7.BC.62 | Shuvalovite | K2(Ca2Na)(SO4)3F |
| 7.BC.65 | Saccoite | Ca2Mn3+2F(OH)8 · 0.5(SO4) |
| 7.BC.65 | Linarite | PbCu(SO4)(OH)2 |
| 7.BC.65 | Therasiaite | (NH4)3KNa2Fe2+Fe3+(SO4)3Cl5 |
| 7.BC.65 | Franksousaite | PbCu(Se6+O4)(OH)2 |
| 7.BC.65 | Munakataite | Pb2Cu2(Se4+O3)(SO4)(OH)4 |
| 7.BC.65 | Schmiederite | Pb2Cu2(Se6+O4)(Se4+O3)(OH)4 |
| 7.BC.70 | Chenite | Pb4Cu(SO4)2(OH)6 |
| 7.BC.75 | Krivovichevite | Pb3Al(OH)6(SO4)(OH) |
| 7.BC.80 | Anhydrokainite | KMg(SO4)Cl |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 0.0000% | 0 | α, β, γ |
| Thorium (Th) | 0.0000% | 0 | α, β, γ |
| Potassium (K) | 9.4392% | 2,926 | β, γ |
For comparison:
- Banana: ~15 Bq per fruit
- Granite: 1,000–3,000 Bq/kg
- EU exemption limit: 10,000 Bq/kg
Note: Risk is shown relative to daily recommended maximum exposure to non-background radiation of 1000 µSv/year. Note that natural background radiation averages around 2400 µSv/year so in reality these risks are probably extremely overstated! With infrequent handling and safe storage natural radioactive minerals do not usually pose much risk.
Interactive Simulator:
Note: The mass selector refers to the mass of radioactive mineral present, not the full specimen, also be aware that the matrix may also be radioactive, possibly more radioactive than this mineral!
Activity: –
| Distance | Dose rate | Risk |
|---|---|---|
| 1 cm | ||
| 10 cm | ||
| 1 m |
The external dose rate (D) from a radioactive mineral is estimated by summing the gamma radiation contributions from its Uranium, Thorium, and Potassium content, disregarding daughter-product which may have a significant effect in some cases (eg 'pitchblende'). This involves multiplying the activity (A, in Bq) of each element by its specific gamma ray constant (Γ), which accounts for its unique gamma emissions. The total unshielded dose at 1 cm is then scaled by the square of the distance (r, in cm) and multiplied by a shielding factor (μshield). This calculation provides a 'worst-case' or 'maximum risk' estimate because it assumes the sample is a point source and entirely neglects any self-shielding where radiation is absorbed within the mineral itself, meaning actual doses will typically be lower. The resulting dose rate (D) is expressed in microsieverts per hour (μSv/h).
D = ((AU × ΓU) + (ATh × ΓTh) + (AK × ΓK)) / r2 × μshield
Other Information
Electrical:
Strongly pyroelectric.
Notes:
Insoluble in water.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Alunite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Alunite
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https://www.mindat.org/min-161.html
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References for Alunite
Reference List:
Haüy, René Just (1801) Traité de Minéralogie (1st ed.) Vol. 2. Chez Louis.p.119 - as Alum de Rome
Schaller, W.T. (1916) Mineralogic notes, series 3. Bulletin 610. US Geological Survey 164 pp. doi:10.3133/b610 pp.150-151
Foshag, William F. (1926) The identity of newtonite with alunite. American Mineralogist, 11 (2) 33-35
Laudermilk, J. D. (1935) Soda-alunite from Molokai, Hawaiian Islands. American Mineralogist, 20 (1) 57-58
Hendricks, Sterling B. (1937) The crystal structure of alunite and the jarosites. American Mineralogist, 22 (6) 773-784
Willard, Max Emery, Proctor, Paul Dean (1946) White Horse alunite deposit, Marysvale, Utah. Economic Geology, 41 (6) 619-643 doi:10.2113/gsecongeo.41.6.619
Pabst, A. (1947) Some computations on svanbergite, woodhouseite and alunite. American Mineralogist, 32 (1-2) 16-30
Brophy, Gerald P., Scott, Earl S., Snellgrove, Richard A. (1962) Sulfate studies II. Solid solution between alunite and jarosite. American Mineralogist, 47 (1-2) 112-126
Wang, R., Bradley, W. F., Steinfink, H. (1965) The crystal structure of alunite. Acta Crystallographica, 18 (2) 249-252 doi:10.1107/s0365110x65000555
Serna, Carlos J., Cortina, C.Parada, Garcia Ramos, José V. (1986) Infrared and Raman study of alunite—jarosite compounds. Spectrochimica Acta Part A: Molecular Spectroscopy, 42 (6). 729-734 doi:10.1016/0584-8539(86)80092-7
Scott, Keith M. (1987) Solid solution in, and classification of, gossan-derived members of the alunite-jarosite family, northwest Queensland, Australia. American Mineralogist, 72 (1-2) 178-187
Jambor, John L. (1999) Nomenclature of the alunite supergroup. The Canadian Mineralogist, 37 (6). 1323-1341
Schukow,, H., Breitinger, D. K., Zeiske, Th., Kubanek, F., Mohr, J., Schwab, R. G. (1999) Localization of Hydrogen and Content of Oxonium Cations in Alunite via Neutron Diffraction. Zeitschrift für anorganische und allgemeine Chemie, 625. 1047-1050 doi:10.1002/(sici)1521-3749(199906)625:6<1047::aid-zaac1047>3.0.co;2-f
Lager, G. A.; Swayze, G. A.; Loong, C.-K.; Rotella, F. J.; Richardson, J. W.; Stoffregen, R. E. (2001) Neutron spectroscopic study of synthetic alunite and oxonium–substituted alunite. The Canadian Mineralogist, 39 (4). 1131-1138 doi:10.2113/gscanmin.39.4.1131
Bishop, J. L. (2005) The visible and infrared spectral properties of jarosite and alunite. American Mineralogist, 90 (7) 1100-1107 doi:10.2138/am.2005.1700
Frost, Ray L., Wills, Rachael-Anne, Weier, Matt L., Martens, Wayde, Theo Kloprogge, J. (2006) A Raman spectroscopic study of alunites. Journal of Molecular Structure, 785 (1) 123-132 doi:10.1016/j.molstruc.2005.10.003
Majzlan, J., Speziale, S., Duffy, T. S., Burns, P. C. (2006) Single-crystal elastic properties of alunite, KAl3(SO4)2(OH)6. Physics and Chemistry of Minerals, 33 (8) 567-573 doi:10.1007/s00269-006-0104-z
Papike, J.J. (2006) Terrestrial analogs of martian sulfates: Major and minor element systematics of alunite-jarosite from Goldfield, Nevada. American Mineralogist, 91 (7) 1197-1200 doi:10.2138/am.2006.2257
Nielsen, U. G., Majzlan, J., Phillips, B., Ziliox, M., Grey, C. P. (2007) Characterization of defects and the local structure in natural and synthetic alunite (K, Na, H3O)Al3(SO4)2(OH)6 by multi-nuclear solid-state NMR spectroscopy. American Mineralogist, 92 (4) 587-597 doi:10.2138/am.2007.2414
Murphy, P. J.; Smith, A. M.L.; Hudson-Edwards, K. A.; Dubbin, W. E.; Wright, K. (2009) Raman and IR spectroscopic studies of alunite-supergroup compounds containing Al, Cr3+, Fe3+ and V3+ at the B site. The Canadian Mineralogist, 47 (3). 663-681 doi:10.3749/canmin.47.3.663
Sato, Eriko, Nakai, Izumi, Miyawaki, Ritsuro, Matsubara, Satoshi (2009) Crystal structures of alunite family minerals: beaverite, corkite, alunite, natroalunite, jarosite, svanbergite, and woodhouseite. Neues Jahrbuch für Mineralogie - Abhandlungen, 185 (3) 313-322 doi:10.1127/0077-7757/2009/0128
Bayliss, P., Kolitsch, U., Nickel, E. H., Pring, A. (2010) Alunite supergroup: recommended nomenclature. Mineralogical Magazine, 74 (5) 919-927 doi:10.1180/minmag.2010.074.5.919
Zema, M., Callegari, A. M., Tarantino, S. C., Gasparini, E., Ghigna, P. (2012) Thermal expansion of alunite up to dehydroxylation and collapse of the crystal structure. Mineralogical Magazine, 76 (3) 613-623 doi:10.1180/minmag.2012.076.3.12
Ehlmann, Bethany L., Swayze, Gregg A., Milliken, Ralph E., Mustard, John F., Clark, Roger N., Murchie, Scott L., Breit, George N., Wray, James J., Gondet, Brigitte, Poulet, Francois, Carter, John, Calvin, Wendy M., Benzel, William M., Seelos, Kimberly D. (2016) Discovery of alunite in Cross crater, Terra Sirenum, Mars: Evidence for acidic, sulfurous waters. American Mineralogist, 101 (7) 1527-1542 doi:10.2138/am-2016-5574
Grigg, Andrew R. C., Notini, Luiza, Kaegi, Ralf, ThomasArrigo, Laurel K., Kretzschmar, Ruben (2024) Structural Effects of Aluminum and Iron Occupancy in Minerals of the Jarosite-Alunite Solid Solution. ACS Earth and Space Chemistry, 8 (2) 194-206 doi:10.1021/acsearthspacechem.3c00174
Ranalli, Anthony J.; Swayze, Gregg A. (2024) Alunite in Cross Crater, Mars: Evidence for a Possible Site of Ancient Life. Astrobiology, 24 (11). 1096-1109 doi:10.1089/ast.2024.0001
McCollom, Thomas M.; Potter-McIntyre, Sally L.; Donaldson, Chris; Reyes, Andres; Moskowitz, Bruce; Solheid, Peter (2025) Rare occurrence of jarosite-alunite solid solutions with intermediate Al-Fe contents in the Jurassic Aztec Sandstone, Nevada, U.S.A. American Mineralogist, 110 (10). 1626-1639 doi:10.2138/am-2024-9423
Localities for Alunite
Showing 1,429 localities.
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The Locality List
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? - Indicates mineral may be doubtful at this locality.
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(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
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Chinkuashih mine, Ruifang District, New Taipei City, Taiwan