Alum-(K)
A valid IMA mineral species - grandfathered
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About Alum-(K)
Formula:
KAl(SO4)2 · 12H2O
Colour:
Colourless, white; colourless in transmitted light.
Lustre:
Vitreous
Hardness:
2
Specific Gravity:
1.757
Crystal System:
Isometric
Member of:
Name:
The name is derived from "alum" since this species is a member of the alum group; the -(K) suffix denotes that it is the K-dominant member of the group. Renamed from potassium alum to alum-(K) in 2008.
Type Locality:
Unique Identifiers
Mindat ID:
3267
Long-form identifier:
mindat:1:1:3267:0
GUID
(UUID V4):
(UUID V4):
d5221316-1bfa-4bdd-a86c-838a80e3696a
IMA Classification of Alum-(K)
Approved, 'Grandfathered' (first described prior to 1959)
Classification of Alum-(K)
7.CC.20
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H2O
C : With medium-sized and large cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H2O
C : With medium-sized and large cations
29.5.5.1
29 : HYDRATED ACID AND NORMAL SULFATES
5 : AB(XO4)2·xH2O
29 : HYDRATED ACID AND NORMAL SULFATES
5 : AB(XO4)2·xH2O
25.6.17
25 : Sulphates
6 : Sulphates of Al and Tl
25 : Sulphates
6 : Sulphates of Al and Tl
Mineral Symbols
As of 2021 there are now IMAâCNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference |
|---|---|---|
| Aum-K | IMAâCNMNC | Warr, L.N. (2021). IMAâCNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Alum-(K)
Vitreous
Transparency:
Transparent
Colour:
Colourless, white; colourless in transmitted light.
Hardness:
2 on Mohs scale
Cleavage:
Poor/Indistinct
{111}, traces.
{111}, traces.
Fracture:
Conchoidal
Density:
1.757 g/cm3 (Measured) 1.753 g/cm3 (Calculated)
Optical Data of Alum-(K)
Type:
Isotropic
Chemistry of Alum-(K)
Mindat Formula:
KAl(SO4)2 · 12H2O
Crystallography of Alum-(K)
Crystal System:
Isometric
Class (H-M):
m3 (2/m 3) - Diploidal
Space Group:
Pa3
Cell Parameters:
a = 12.157(3) Å
Unit Cell V:
1,796.72 Ă
Âł (Calculated from Unit Cell)
Z:
4
Morphology:
Crystals octahedral if precipitated from pure water solution; cubic from alkaline solutions. Commonly massive with a columnar or granular structure; stalactitic, mealy coatings.
Twinning:
On {111}, very rare.
Crystallographic forms of Alum-(K)
Crystal Atlas:
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Potassiumalum no.3 - Goldschmidt (1913-1926)
Potassiumalum no.27 - Goldschmidt (1913-1926)
Potassiumalum no.28 - 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) |
|---|---|---|---|---|---|---|---|
| 0019046 | Alum-(K) | Larson A C, Cromer D T (1967) Refinement of the alum structures. III. X-ray study of the a alums, K, Rb and NH4Al(SO4)2*12H2O Acta Crystallographica 22 793-800 |  | 1967 | Synthetic | 0 | 293 |
| 0009911 | Alum-(K) | Nyburg S C, Steed J, Aleksovska S, Petrusevski V M (2000) Structure of the alums. I. On the sulfate group disorder in the alpha-alums Acta Crystallographica B56 204-209 | | 2000 | synthetic | 0 | 293 |
| 0009912 | Alum-(K) | Nyburg S C, Steed J, Aleksovska S, Petrusevski V M (2000) Structure of the alums. I. On the sulfate group disorder in the alpha-alums Acta Crystallographica B56 204-209 | | 2000 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
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Radiation - Copper Kα
Data courtesy of RRUFF project at University of Arizona, used with permission.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 45a : [Sulfates, arsenates, selenates, antimonates] | |
| 47a : [Near-surface hydration of prior minerals] | |
| 47b : [Sulfates and sulfites] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
Type Occurrence of Alum-(K)
Synonyms of Alum-(K)
Other Language Names for Alum-(K)
German:Kalialaun (in part)
Kalinischer Alumsulphat (in part)
Kalinischer Alumsulphat (in part)
Simplified Chinese:éŸæçŸ
éŸæçŸçł
éŸæçŸçł
Varieties of Alum-(K)
| Thallium-bearing Alum-(K) | Empirical formula (Fornovolasco material): (K0.74Tl0.10)Σ0.84(Al0.84Fe0.14)Σ0.98S2.03O8·12H2O. |
Relationship of Alum-(K) to other Species
Member of:
Other Members of this group:
| Alum-(Na) | NaAl(SO4)2 · 12H2O | Iso. m3 (2/m 3) : Pa3 |
| Lanmuchangite | Tl+Al(SO4)2 · 12H2O | Iso. m3 (2/m 3) : Pa3 |
| Tschermigite | (NH4)Al(SO4)2 · 12H2O | Iso. m3 (2/m 3) : Pa3 |
Common Associates
Associated Minerals Based on Photo Data:
| 5 photos of Alum-(K) associated with Sulphur | S8 |
| 3 photos of Alum-(K) associated with Halotrichite | FeAl2(SO4)4 · 22H2O |
| 2 photos of Alum-(K) associated with Pickeringite | MgAl2(SO4)4 · 22H2O |
| 2 photos of Alum-(K) associated with Magnanelliite | K3Fe3+2(SO4)4(OH)(H2O)2 |
| 2 photos of Alum-(K) associated with Krausite | KFe(SO4)2 · H2O |
| 1 photo of Alum-(K) associated with Tamarugite | NaAl(SO4)2 · 6H2O |
| 1 photo of Alum-(K) associated with Hexahydrite | MgSO4 · 6H2O |
| 1 photo of Alum-(K) associated with Copiapite Group | |
| 1 photo of Alum-(K) associated with Pyrite | FeS2 |
| 1 photo of Alum-(K) associated with Giacovazzoite | K5Fe3+3O(SO4)6 · 10H2O |
Related Minerals - Strunz-mindat Grouping
| 7.CC. | Cobaltoblödite | Na2Co(SO4)2 · 4H2O |
| 7.CC. | Andychristyite | PbCu2+Te6+O5(H2O) |
| 7.CC. | Ammoniovoltaite | (NH4)2Fe2+5Fe3+3Al(SO4)12(H2O)18 |
| 7.CC.05 | Krausite | KFe(SO4)2 · H2O |
| 7.CC.10 | Tamarugite | NaAl(SO4)2 · 6H2O |
| 7.CC.15 | Kalinite | KAl(SO4)2 · 11H2O |
| 7.CC.15 | Mendozite | NaAl(SO4)2 · 11H2O |
| 7.CC.20 | Lonecreekite | (NH4)Fe3+(SO4)2 · 12H2O |
| 7.CC.20 | Alum-(Na) | NaAl(SO4)2 · 12H2O |
| 7.CC.20 | Tschermigite | (NH4)Al(SO4)2 · 12H2O |
| 7.CC.20 | Lanmuchangite | Tl+Al(SO4)2 · 12H2O |
| 7.CC.25 | Voltaite | K2Fe2+5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.25 | Zincovoltaite | K2Zn5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.25 | Pertlikite | K2(Fe2+,Mg)2Mg4Fe3+2Al(SO4)12 · 18H2O |
| 7.CC.25 | Ammoniomagnesiovoltaite | (NH4)2Mg2+5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.25 | Magnesiovoltaite | K2Mg5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.30 | Kröhnkite | Na2Cu(SO4)2 · 2H2O |
| 7.CC.35 | Ferrinatrite | Na3Fe(SO4)3 · 3H2O |
| 7.CC.40 | Goldichite | KFe(SO4)2 · 4H2O |
| 7.CC.45 | Löweite | Na12Mg7(SO4)13 · 15H2O |
| 7.CC.50 | Blödite | Na2Mg(SO4)2 · 4H2O |
| 7.CC.50 | Nickelblödite | Na2(Ni,Mg)(SO4)2 · 4H2O |
| 7.CC.50 | Changoite | Na2Zn(SO4)2 · 4H2O |
| 7.CC.55 | Leonite | K2Mg(SO4)2 · 4H2O |
| 7.CC.55 | Mereiterite | K2Fe(SO4)2 · 4H2O |
| 7.CC.60 | Boussingaultite | (NH4)2Mg(SO4)2 · 6H2O |
| 7.CC.60 | Cyanochroite | K2Cu(SO4)2 · 6H2O |
| 7.CC.60 | Mohrite | (NH4)2Fe(SO4)2 · 6H2O |
| 7.CC.60 | Nickelboussingaultite | (NH4)2Ni(SO4)2 · 6H2O |
| 7.CC.60 | Picromerite | K2Mg(SO4)2 · 6H2O |
| 7.CC.60 | Nickelpicromerite | K2Ni(SO4)2 · 6H2O |
| 7.CC.60 | Katerinopoulosite | (NH4)2Zn(SO4)2 · 6H2O |
| 7.CC.65 | Polyhalite | K2Ca2Mg(SO4)4 · 2H2O |
| 7.CC.70 | Leightonite | K2Ca2Cu(SO4)4 · 2H2O |
| 7.CC.75 | Amarillite | NaFe(SO4)2 · 6H2O |
| 7.CC.80 | Konyaite | Na2Mg(SO4)2 · 5H2O |
| 7.CC.85 | Wattevilleite | Na2Ca(SO4)2 · 4H2O (?) |
| 7.CC.85 | Xocolatlite | Ca2Mn4+2(Te6+O6)2 · H2O |
| 7.CC.90 | Eckhardite | (Ca,Pb)Cu2+Te6+O5(H2O) |
Other Information
Thermal Behaviour:
Rapid heating to below red heat, it intumesces and forms a bulky, porous mass of the anhydrous sulfate ("burnt alum").
Notes:
Soluble in water. Melts in its water of crystallization at 91 deg.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Alum-(K)
mindat.org URL:
https://www.mindat.org/min-3267.html
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References for Alum-(K)
Localities for Alum-(K)
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
â - Click for references and 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).
All localities listed without proper references should be considered as questionable.
Argentina | |
| Saravia (1960) |
| Bengochea +1 other reference |
Austria | |
| Strasser (1989) |
| Lapis 19 (7/8) |
Bolivia | |
| [www.hedegaard.com] +1 other reference |
| Salomon Rivas & Federico Ahlfeld (1998) |
Chile | |
| Chukanov et al. (2016) |
| Palache et al. (1951) |
| Aguilera et al. (2016) | |
China | |
| Acta Mineral. Sinica: 21 (3) |
| Wen et al. (2020) |
| Liu et al. (2024) |
Czech Republic | |
| Breiter K. (1976) |
| Breiter K. (1976) | |
| Breiter K. (1976) |
| Breiter K. (1976) |
| Breiter K. (1976) |
| HrĆĄelovĂĄ et al. (2013) |
Germany | |
| Walenta (1992) |
| Aufschluss 1984 (1) |
| Mineralogical Society of America - ... |
| WeiĂ (1990) |
| www.mg-mineralien-fossilien.de (n.d.) +2 other references |
| BlaĂ et al. (1996) +1 other reference |
| Frenzel (1964) |
| H. Schneider: "Saarland" et al. (Berlin, Stuttgart) |
| Mineralogical Society of America - ... |
| EDX and XRD confirmed by Dr. Th. Witzke |
| T. Witzke & F. RĂŒger: Lapis 1998 (7/8) |
| Mineralogical Society of America - ... |
Hungary | |
| GEODA 2007/1 |
| LovĂĄsz & SzabĂł (2014) |
| Own collecting and analysed (2005) |
| Geoda | |
Iran | |
| Bariand et al. (1977) |
Ireland | |
| Alfredo Petrov specimen (obtained from Dr Marco Marcchesini) |
Italy | |
| Scacchi A. (1849) +1 other reference |
| Mineralogical Society of America - ... | |
| Russo et al. (2017) |
| Mormone et al. (2015, April) +1 other reference | |
| Russo et al. (2017) |
| Russo +1 other reference |
| Russo et al. (2004) | |
| Russo et al. (2004) +1 other reference |
| Pelloux (1927) +3 other references | |
| Del Caldo A. et al. (1973) +1 other reference |
| Fernando Caboni et al. (2024) |
| Fernando Caboni et al. (2024) | |
| D'Angeli et al. (2018) |
| Russo (2006) |
| Russo (2006) |
| Campostrini I. et al - Vulcano: ein ... +3 other references |
| Cossa (1881) +3 other references |
| Panichi (1914) +2 other references |
| COSSA A. (1881) | |
| Campostrini et al. (2011) | |
| Bazzoni et al. (2015) |
| Biagioni et al. (2019) +1 other reference |
| Biagioni et al. (2011) +1 other reference |
| Mauro D. (2016) +1 other reference | |
| 9 (2) +3 other references |
Japan | |
| Ibaraki et al. (1991) |
| Ibaraki et al. (1991) | |
| Alfredo Petrov collection +1 other reference |
Norway | |
| L. Kruszewski specimen |
Pakistan | |
| M. Qasim Jan et al. (1985) |
Poland | |
| MarszaĆek +2 other references |
| Lis et al. (1986) |
| Lis et al. (1986) |
| Lis et al. (1986) |
| Lis et al. (1986) |
| Lis et al. (1986) |
| Ciesielczuk et al. (2014) |
| Berg G. 1935: ErlÀuterungen zu Blatt ... |
| Lis et al. (1986) |
| Lis et al. (1986) |
| Lis et al. (1986) |
| Lis et al. (1986) |
| Lis et al. (1986) |
| Lis et al. (1986) |
| Lis et al. (1986) |
| Lis et al. (1986) |
| Lis et al. (1986) |
| Ćukasz Kruszewski (2012) |
Portugal | |
| Flahaut et al. (2018, September) |
| Luigi Chiappino collection | |
Romania | |
| Ćukasz Kruszewski PXRD & pXRF analysis ... |
Russia | |
| Okrugin (2004) |
South Africa | |
| Martini (1997) |
South Korea | |
| Rutgers College Geological Museum ... |
Switzerland | |
| Erik Vercammen collection |
UK | |
| Ford et al. (1993) |
| Hall (1868) |
| Palache et al. (1951) |
| Livingstone et al. (1983) |
USA | |
| Anatoly Kasatkin analyses |
| Hanson et al. (2008) |
| Palache et al. (1951) +1 other reference |
| Dana 7: I: 143 +2 other references |
| California State University (2000) +1 other reference |
| Van Nostrand Reinholt Press: 265. +3 other references |
| Mineralogical Society of America - ... |
| Eckel et al. (1997) |
| Minerals of Colorado (1997) |
| Erd et al. (1960) |
| Erd et al. (1960) |
| Erd et al. (1960) |
| Erd et al. (1960) | |
| Erd et al. (1960) | |
| Uwe Kolitsch (SXRD-analysis) +3 other references |
| Mineralogical Society of America - ... |
| Carlson (2015) |
| Carlson (2015) |
| Carlson (2015) |
| Montgomery (Jan, 1963) +2 other references |
| Downey et al. (1974) +1 other reference |
| Bernard et al. (2004) |
| Bullock (1981) |
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Lichtenberg Absetzer dump, Kauern, Greiz District, Thuringia, Germany