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Al2(SO4)3 · 17H2O
Colorless in crystals, aggregates white, or pale yellow or red from impurities.
Vitreous, Silky
1½ - 2
Crystal System:
From the Latin "alum" and the Greek γεννώ ("genno"), "to create".
A hydrated aluminium sulfate. The highest hydrate of natural Al sulphate, when compared to 'meta-alunogen', Unnamed (Al Sulphate-Hydrate), and UM1976-22-SO:AlFeH. Also the hydrated counterpart of millosevichite.

At high temperates, alunogen may dehydrate to its pentahydrate, Unnamed (Al Sulphate-Hydrate).

Compare also 'UM1987-13-SO:AlH' and 'UM1976-22-SO:AlFeH'.

Classification of Alunogen

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

7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H2O
B : With only medium-sized cations
Dana 7th ed.:

8 : A2(XO4)3·H2O

25 : Sulphates
6 : Sulphates of Al and Tl

Physical Properties of Alunogen

Vitreous, Silky
Colorless in crystals, aggregates white, or pale yellow or red from impurities.
colorless in transmitted light.
1½ - 2 on Mohs scale

Optical Data of Alunogen

Biaxial (+)
RI values:
nα = 1.473 nβ = 1.474 nγ = 1.480
Measured: 31° to 69°, Calculated: 46°
Max Birefringence:
δ = 0.007
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:

Chemical Properties of Alunogen

Al2(SO4)3 · 17H2O
IMA Formula:
Al2(SO4)3(H2O)12 · 5H2O

Crystallography of Alunogen

Crystal System:
Class (H-M):
1 - Pinacoidal
Crystals rare, small; prismatic [001] or {010} with a hexagonal outline about [010]; very complex, with about 60 forms noted. Commonly as delicate fibrous masses or crusts; effloresences; massive, fibrous to 5mm.

On {010}.

X-Ray Powder Diffraction

Image Loading

Radiation - Copper Kα
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Synonyms of Alunogen

Other Language Names for Alunogen

Varieties of Alunogen


A variety of Alunogen containing some P2O5

Common Associates

EpsomiteMgSO4 · 7H2O
EpsomiteMgSO4 · 7H2O
GypsumCaSO4 · 2H2O
HalotrichiteFeAl2(SO4)4 · 22H2O
MelanteriteFeSO4 · 7H2O
PickeringiteMgAl2(SO4)4 · 22H2O
Associated Minerals Based on Photo Data:
Coquimbite23 photos of Alunogen associated with Coquimbite on
Copiapite14 photos of Alunogen associated with Copiapite on
Chalcanthite12 photos of Alunogen associated with Chalcanthite on
Metavoltine7 photos of Alunogen associated with Metavoltine on
Voltaite7 photos of Alunogen associated with Voltaite on
Halotrichite7 photos of Alunogen associated with Halotrichite on
Jarosite4 photos of Alunogen associated with Jarosite on
Römerite4 photos of Alunogen associated with Römerite on
Meta-alunogen3 photos of Alunogen associated with Meta-alunogen on
Cuprian Melanterite3 photos of Alunogen associated with Cuprian Melanterite on

Related Minerals - Nickel-Strunz Grouping

7.CB.05Dwornikite(Ni,Fe)SO4 · H2O
7.CB.05GunningiteZnSO4 · H2O
7.CB.05KieseriteMgSO4 · H2O
7.CB.05Poitevinite(Cu,Fe,Zn)SO4 · H2O
7.CB.05SzmikiteMnSO4 · H2O
7.CB.05SzomolnokiteFeSO4 · H2O
7.CB.05CobaltkieseriteCoSO4 · H2O
7.CB.07SanderiteMgSO4 · 2H2O
7.CB.10BonattiteCuSO4 · 3H2O
7.CB.15Aplowite(Co,Mn,Ni)SO4 · 4H2O
7.CB.15Boyleite(Zn,Mg)SO4 · 4H2O
7.CB.15Ilesite(Mn,Zn,Fe)SO4 · 4H2O
7.CB.15RozeniteFeSO4 · 4H2O
7.CB.15StarkeyiteMgSO4 · 4H2O
7.CB.15DrobeciteCdSO4 · 4H2O
7.CB.15CranswickiteMgSO4 · 4H2O
7.CB.20ChalcanthiteCuSO4 · 5H2O
7.CB.20JôkokuiteMnSO4 · 5H2O
7.CB.20PentahydriteMgSO4 · 5H2O
7.CB.20SiderotilFeSO4 · 5H2O
7.CB.25Bianchite(Zn,Fe)SO4 · 6H2O
7.CB.25Chvaleticeite(Mn,Mg)SO4 · 6H2O
7.CB.25FerrohexahydriteFeSO4 · 6H2O
7.CB.25HexahydriteMgSO4 · 6H2O
7.CB.25Moorhouseite(Co,Ni,Mn)SO4 · 6H2O
7.CB.25Nickelhexahydrite(Ni,Mg,Fe)SO4 · 6H2O
7.CB.30RetgersiteNiSO4 · 6H2O
7.CB.35BieberiteCoSO4 · 7H2O
7.CB.35BoothiteCuSO4 · 7H2O
7.CB.35MallarditeMnSO4 · 7H2O
7.CB.35MelanteriteFeSO4 · 7H2O
7.CB.35Zincmelanterite(Zn,Cu,Fe)SO4 · 7H2O
7.CB.35Alpersite(Mg,Cu)[SO4] · 7H2O
7.CB.40EpsomiteMgSO4 · 7H2O
7.CB.40GoslariteZnSO4 · 7H2O
7.CB.40MorenositeNiSO4 · 7H2O
7.CB.45Meta-alunogenAl2(SO4)3 · 12H2O
7.CB.50AluminocoquimbiteFeAl(SO4)3 · 9H2O
7.CB.55CoquimbiteFe2-xAlx(SO4)3 · 9H2O, x ~0.5
7.CB.55ParacoquimbiteFe2(SO4)3 · 9H2O
7.CB.55Rhomboclase(H5O2)Fe3+(SO4)2 · 2H2O
7.CB.60KorneliteFe2(SO4)3 · 7H2O
7.CB.65QuenstedtiteFe2(SO4)3 · 11H2O
7.CB.75LishizheniteZnFe2(SO4)4 · 14H2O
7.CB.75RömeriteFe2+Fe3+2(SO4)4 · 14H2O
7.CB.80RansomiteCuFe2(SO4)4 · 6H2O
7.CB.85ApjohniteMn2+Al2(SO4)4 · 22H2O
7.CB.85BíliniteFe2+Fe3+2(SO4)4 · 22H2O
7.CB.85Dietrichite(Zn,Fe2+,Mn2+)Al2(SO4)4 · 22H2O
7.CB.85HalotrichiteFeAl2(SO4)4 · 22H2O
7.CB.85PickeringiteMgAl2(SO4)4 · 22H2O
7.CB.90MeridianiiteMgSO4 · 11H2O

Related Minerals - Hey's Chemical Index of Minerals Grouping

25.6.1RostiteAl(SO4)(OH) · 5H2O
25.6.2JurbaniteAl(SO4)(OH) · 5H2O
25.6.3KhademiteAl(SO4)F · 5H2O
25.6.4Meta-aluminiteAl2(SO4)(OH)4 · 5H2O
25.6.5AluminiteAl2(SO4)(OH)4 · 7H2O
25.6.6Meta-alunogenAl2(SO4)3 · 12H2O
25.6.8FelsőbányaiteAl4(SO4)(OH)10 · 4H2O
25.6.9BasaluminiteAl4(SO4)(OH)10 · 4H2O
25.6.10HydrobasaluminiteAl4(SO4)(OH)10 · 12-36H2O
25.6.11ZaheriteAl12(SO4)5(OH)26 · 20H2O
25.6.12TamarugiteNaAl(SO4)2 · 6H2O
25.6.13MendoziteNaAl(SO4)2 · 11H2O
25.6.14Alum-(Na)NaAl(SO4)2 · 12H2O
25.6.16KaliniteKAl(SO4)2 · 11H2O Not confirmed
25.6.17Alum-(K)KAl(SO4)2 · 12H2O
25.6.20Tschermigite(NH4)Al(SO4)2 · 12H2O

Other Information

Readily soluble in water. Taste alumlike, acid and sharp.
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 Alunogen

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Beudant, F.S. (1824) Trailé élémentaire de Minéralogie, 8vo, Paris: 449. [as Hydrotrisulfate d'alumine]
Mill (1828) Quarterly Journal of Science, Literature, and Art, London: 25: 382. [as Davite]
Beudant, F.S. (1832) Alunogène, sulfate d’alumine. Trailé élémentaire de Minéralogie, second edition, 2 volumes: 2: 488-492. [as Alunogène]
Shepard C.U. (1835) Treatise on Mineralogy. First edition: vols. 2, 3: 188. [as Solfatarite]
Glocker, E.F. (1839) Handbuch der Mineralogie, 2nd. edition, Nürnberg: 689. [as Keramohalite]
Huot, J.J. (1841) Manuel de Minéralogie. 2 volumes, Paris: 2: 451. [as Saldanite]
Glocker, E.F. (1847) Generum et specierum mineralien secundum ordines naturals digestorum synopsis. Halle: 297. [as Stypterit]
Hausmann, J.F.L. (1847) Handbuch der Mineralogie 3 volumes, Göttingen. Second edition: vol. 2, in two parts: 2: 1174. [as Halotrichit]
Rammelsberg, C.F. (1875) Handbuch der Mineralchemie. second edition: 269. [as Haarsalz]
Jirkovsky (1928) cited in Neues Jahrbuch für Mineralogie, Geologie und Paleontologie, Heidelberg, Stuttgart: I: 106.
Larsen, E.S., Steiger, G. (1928) Dehydration and optical studies of alunogen, nontronite, and griffithite: American Journal of Science, 5th. series: 15: 1-19.
Lausen, C. (1928) Hydrous sulphates formed under fumerolic conditions at the United Verde Mine. American Mineralogist: 13: 208.
Hintze, C. (1929) Handbuch der Mineralogie. Berlin and Leipzig. 6 volumes: 1 [3B]: 4404.
Petrov (1933) Trav. Inst. Pétrog. Ac. Sc. U.R.S.S., no. 3: 89.
Zavaritsky (1935) Trans. Centr. Geol. & Prosp. Inst., Leningrad, no. 35.
Gordon, S.G. (1942) Results of the Chilean mineralogical expedition of 1938. Part VII.—The crystallography of alunogen, meta-alunogen and pickeringite. Notulae Naturae of The Academy of Natural Sciences of Philadelphia: 101: 1-9.
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. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged, 1124 pp.: 537-540.
Menchetti, S., Sabelli, C. (1974) Alunogen. Its structure and twinning. Tschermaks Mineralogische und Petrographische Mitteilungen: 21: 164-178.
Fang, J.H., Robinson, P.D. (1976) Alunogen, Al2(H2O)12(SO4)3·5H2O: Its atomic arrangement and water content. American Mineralogist: 61: 311-317.
Bariand, P., Cesbron, F., Berthelon, J.-P. (1977) Les sulfates de fer de Saghand près de Yazd (Iran). Mémoire Hors-Série de la Société Géologique de France: 8: 77-85.

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Localities for Alunogen

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