Polyhalite
A valid IMA mineral species - grandfathered
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About Polyhalite
Formula:
K2Ca2Mg(SO4)4 · 2H2O
Colour:
Colourless, white, pink, red, grey; colourless in transmitted light.
Lustre:
Vitreous, Resinous
Hardness:
2½ - 3½
Specific Gravity:
2.78
Crystal System:
Triclinic
Name:
Named from the Greek words meaning "many" and "salt".
Unique Identifiers
Mindat ID:
3259
Long-form identifier:
mindat:1:1:3259:5
GUID
(UUID V4):
(UUID V4):
3044d6af-adf2-486f-9c3b-b3ee1d07dc3a
IMA Classification of Polyhalite
Approved, 'Grandfathered' (first described prior to 1959)
First published:
1817
Classification of Polyhalite
7.CC.65
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
29.4.5.1
29 : HYDRATED ACID AND NORMAL SULFATES
4 : AmBn(XO4)p·xH2O, with (m+n):p < 3:2 and > 1:1
29 : HYDRATED ACID AND NORMAL SULFATES
4 : AmBn(XO4)p·xH2O, with (m+n):p < 3:2 and > 1:1
25.4.10
25 : Sulphates
4 : Sulphates of Ca, Sr and Ba
25 : Sulphates
4 : Sulphates of Ca, Sr and Ba
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference |
|---|---|---|
| Plhl | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Polyhalite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Polyhalite
Vitreous, Resinous
Transparency:
Transparent
Colour:
Colourless, white, pink, red, grey; colourless in transmitted light.
Comment:
Salmon-pink to brick-red due to iron oxide inclusions.
Streak:
White
Hardness:
2½ - 3½ on Mohs scale
Cleavage:
Perfect
{101}, perfect
{101}, perfect
Parting:
On {010} (foliated varities).
Density:
2.78 g/cm3 (Measured) 2.763 g/cm3 (Calculated)
Comment:
Calculated density from Bindi (2005).
Optical Data of Polyhalite
Type:
Biaxial (-)
RI values:
nα = 1.546 - 1.548 nβ = 1.558 - 1.562 nγ = 1.567
2V:
Measured: 60° to 62°, Calculated: 60° to 80°
Max Birefringence:
δ = 0.021
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Low
Dispersion:
none
Chemistry of Polyhalite
Mindat Formula:
K2Ca2Mg(SO4)4 · 2H2O
Crystallography of Polyhalite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Cell Parameters:
a = 6.975(3) Å, b = 6.984(3) Å, c = 8.899(3) Å
α = 104.01(3)°, β = 101.19(3)°, γ = 114.10(6)°
α = 104.01(3)°, β = 101.19(3)°, γ = 114.10(6)°
Ratio:
a:b:c = 0.999 : 1 : 1.274
Unit Cell V:
362.3 ų
Z:
1
Morphology:
Crystals small and rare; tabular {010} or elongated [001] and exhibiting numerous forms. Commonly massive, fibrous to foliated.
Twinning:
On {010} and {100}, very common and often polysynthetic.
Comment:
Cell parameters from Bindi (2005).
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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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) |
|---|---|---|---|---|---|---|---|
| 0010450 | Polyhalite | Bindi L (2005) Reinvestigation of the crystal structure of polyhalite, K2Ca2Mg(SO4)4*2H2O Acta Crystallographica E61 i135-i136 |  | 2005 | 0 | 293 | |
| 0015636 | Polyhalite | Schlatti M, Sahl K, Zemann A, Zemann J (1970) Die kristallstruktur des polyhalits, K2Ca2Mg(SO4)4(H2O)2 Tschermaks Mineralogische und Petrographische Mitteilungen 14 75-86 | 1970 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.18 Å | (100) |
| 2.913 Å | (25) |
| 2.890 Å | (25) |
| 2.849 Å | (25) |
| 2.945 Å | (20) |
| 6.00 Å | (14) |
| 2.904 Å | (14) |
Comments:
ICDD 21-982.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 21 : Chemically precipitated carbonate, phosphate, iron formations | |
| 25 : Evaporites (prebiotic) | |
| Stage 7: Great Oxidation Event | <2.4 |
| 45a : [Sulfates, arsenates, selenates, antimonates] | |
| 47a : [Near-surface hydration of prior minerals] | |
| 47b : [Sulfates and sulfites] |
Geological Setting:
Oceanic salt deposits; rarely as a volcanic product.
Type Occurrence of Polyhalite
General Appearance of Type Material:
Compact fibrous.
Geological Setting of Type Material:
Evaporite deposit.
Associated Minerals at Type Locality:
Reference:
Stromeyer, F. (1817) Ein neu entdecktes Metall und Analyse eines neuen Minerals. Journal für Chemie und Physik: 21: 297-306.
Synonyms of Polyhalite
Other Language Names for Polyhalite
Common Associates
Associated Minerals Based on Photo Data:
| 5 photos of Polyhalite associated with Halite | NaCl |
| 3 photos of Polyhalite associated with Iranite | Pb10Cu(CrO4)6(SiO4)2(OH)2 |
| 3 photos of Polyhalite associated with Chromium-bearing Wulfenite | Pb(Mo,Cr)O4 |
| 3 photos of Polyhalite associated with Anhydrite | CaSO4 |
| 2 photos of Polyhalite associated with Gypsum | CaSO4 · 2H2O |
| 2 photos of Polyhalite associated with Metavoltine | K2Na6Fe2+Fe3+6O2(SO4)12 · 18H2O |
| 2 photos of Polyhalite associated with Sideronatrite | Na2Fe(SO4)2(OH) · 3H2O |
| 1 photo of Polyhalite associated with Wulfenite | Pb(MoO4) |
| 1 photo of Polyhalite associated with Mimetite | Pb5(AsO4)3Cl |
| 1 photo of Polyhalite associated with Blödite | Na2Mg(SO4)2 · 4H2O |
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-(K) | KAl(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.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
Notes:
Soluble in H2O, with precipitation of gypsum and perhaps
syngenite. Nearly tasteless.
syngenite. Nearly tasteless.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Industrial Uses:
Most common potassium mineral in Carlsbad, New Mexico deposits.
Polyhalite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Polyhalite
mindat.org URL:
https://www.mindat.org/min-3259.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Polyhalite
Reference List:
(1932) Mineralogy of drill cores from the potash field of New Mexico and Texas. Bulletin Vol. 833. US Geological Survey doi:10.3133/b833 p.73
(1934) The microscopic determination of the nonopaque minerals. Bulletin Vol. 848. US Geological Survey doi:10.3133/b848 p.159
Ramsdell, Lewis S. (1935) An x-ray study of the system K2SO4-MgSO4-CaSO4. American Mineralogist, 20 (8) 569-574
Peacock, M. A. (1938) The relation of leightonite to polyhalite. American Mineralogist, 23 (1) 38-45
PERTHUISOT, J.-P. (1971) Recent Polyhalite from Sebkha el Melah (Tunisia). Nature Physical Science, 232. 186-187 doi:10.1038/physci232186a0
Bindi, Luca (2005) Reinvestigation of polyhalite, K2Ca2Mg(SO4)4·2H2O. Acta Crystallographica Section E Structure Reports Online, 61 (8) doi:10.1107/s1600536805020507
Lane, M. D. (2007) Mid-infrared emission spectroscopy of sulfate and sulfate-bearing minerals. American Mineralogist, 92 (1) 1-18 doi:10.2138/am.2007.2170
Schorn, Anja, Neubauer, Franz, Bernroider, Manfred (2013) Polyhalite microfabrics in an Alpine evaporite mélange: Hallstatt, Eastern Alps. Journal of Structural Geology, 46. 57-75 doi:10.1016/j.jsg.2012.10.006
Xu, Hongwu, Guo, Xiaofeng, Bai, Jianming (2017) Thermal behavior of polyhalite: a high-temperature synchrotron XRD study. Physics and Chemistry of Minerals, 44 (2) 125-135 doi:10.1007/s00269-016-0842-5
Localities for Polyhalite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - 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.
Austria | |
| Walter et al. (2016) |
| gisgba.geologie.ac.at (n.d.) |
| Strasser (1989) |
| Strasser (1989) |
| Strasser (1989) |
| Exel (1993) |
| Exel (1993) |
| Stromeyer (1817) +1 other reference |
| Exel (1993) +1 other reference |
Bolivia | |
| - (unpublished thesis) |
Canada | |
| Boehner (1986) |
| Shang (2000) |
Chile | |
| Aguilera et al. (2016) |
| Collao et al. (2002) |
| Marta et al. (1996) +1 other reference | |
| Arturo Molina collection | |
China | |
| Mili Wang (1982) |
| Cui et al. (2024) |
| Dongsheng Hu (1990) +1 other reference |
| Botao Li et al. (2010) +1 other reference | |
| Shaoxiu Yang (1991) |
| Shaoxiu Yang (1991) | |
| Zhongde Zhu (1988) |
| Zhang Bing et al. (2018) |
| Xuanzhen Huan (2004) |
| Yaoting Lin and Jinquan He (2004) |
| Bingxiao Li (1992) +1 other reference |
| Lichun Ma et al. (2010) | |
| Chenglin Liu et al. (2008) | |
| Bingxiao Li (1992) |
France | |
| Palache et al. (1951) |
Germany | |
| |
| Weiß (1990) |
| Krah et al. (1988) | |
| Weiß (1990) |
| Weiß (1990) |
| Weiß (1990) |
| Füchtbauer et al. (1956) |
| Bode "Mineralien und Fundstellen BRD" ... +1 other reference |
| mrdata.usgs.gov (n.d.) |
| Wittern (2001) |
| www.mineralienatlas.de (n.d.) |
| |
| C. Zinken (1865) |
| ... | |
| T. Witzke & F. Rüger: Lapis 1998 (7/8) |
| Effmert +1 other reference |
| Effmert et al. (2007) | |
| Junker (2013) |
| W.I. Borrisenkow (1968) |
Greece | |
| |
| Branko Rieck collection | |
| Smith et al. (1964) |
India | |
| Sinha et al. (2003) |
Iran | |
| Palache et al. (1951) |
Italy | |
| Russo et al. (2004) |
| Russo et al. (2004) | |
| Roveri M. et al. (2006) |
| Mezzadri (1988) |
| www.cse.speleo.it +1 other reference |
Kazakhstan | |
| ERCOSPAN (2011) |
| ERCOSPAN (2011) |
| Pekov et al. (2020) | |
| Pekov et al. (1993) |
| Mineralogical Society of America - ... +2 other references |
Kenya | |
| Bowell et al. (1996) |
Mexico | |
| Holser (1966) |
Netherlands | |
| T.G. Nijland |
| nlog.nitg.tno.nl (n.d.) |
| T.G. Nijland |
| Pichat (2022) | |
North Sea | |
Pakistan | |
| www.scribd.com (n.d.) |
Poland | |
| Jirásek +7 other references |
Romania | |
| Har +3 other references |
Russia | |
| Sokol et al. (2022) |
| Mazurov et al. (2007) +1 other reference |
| Palache et al. (1951) |
| Naumov et al. (2008) |
Spain | |
| Calvo (2014) |
| García del Cura (1979) |
| Herrero +4 other references | |
| |
| Garrett (2001) | |
Tunisia | |
| Smykatz-Kloss et al. (2010) |
Turkey | |
| Irion et al. (1968) +1 other reference |
Turkmenistan | |
| Evseev (1995) |
UK | |
| F. H. Stewart (1965) +1 other reference |
| rruff.geo.arizona.edu (n.d.) |
| Palache et al. (1951) |
| Armstrong et al. (1951) |
| Armstrong et al. (1951) | |
| Smith et al. (2014) | |
| Smith et al. (2014) |
| Smith et al. (2014) |
| uk.angloamerican.com (n.d.) |
| Smith et al. (2014) | |
| Smith et al. (2014) | |
| Kemp et al. (2016) | |
Ukraine | |
| Palache et al. (1951) |
USA | |
| Peirce (1969) +1 other reference |
| Adams et al. (2014) |
| Heinrich et al. (2004) |
| Heinrich et al. (2004) |
| Castor et al. (2004) |
| Palache et al. (1951) +1 other reference |
| Northrop et al. (1996) | |
| Hawley +5 other references |
| Philip (2013) | |
| King (n.d.) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| Northrop et al. (1996) | |
| Bullock (1981) |
| Bullock (1981) | |
| Bullock (1981) | |
| Bullock (1981) | |
| Bullock (1981) |
| Bullock (1981) |
| Bullock (1981) |
| Bullock (1981) | |
Uzbekistan | |
| Slyusareva (1969) +1 other reference |
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Salt mine, Hallstatt, Gmunden District, Upper Austria, Austria