Polyhalite (original) (raw)
A valid IMA mineral species - grandfathered
About PolyhaliteHide
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Formula:
K2Ca2Mg(SO4)4 · 2H2O
Colour:
Colourless, white, pink, red, grey; colourless in transmitted light.
Lustre:
Vitreous, Resinous
Name:
Named from the Greek words meaning "many" and "salt".
Unique IdentifiersHide
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Long-form identifier:
mindat:1:1:3259:5
3044d6af-adf2-486f-9c3b-b3ee1d07dc3a
IMA Classification of PolyhaliteHide
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Approved, 'Grandfathered' (first described prior to 1959)
Type description reference:
Classification of PolyhaliteHide
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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
29.4.5.1
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
Mineral SymbolsHide
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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 PolyhaliteHide
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Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Sorry, your browser doesn't support HTML5 audio. | Jolyon Ralph | United Kingdom |
Physical Properties of PolyhaliteHide
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Colour:
Colourless, white, pink, red, grey; colourless in transmitted light.
Comment:
Salmon-pink to brick-red due to iron oxide inclusions.
Cleavage:
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 PolyhaliteHide
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RI values:
_n_α = 1.546 - 1.548 _n_β = 1.558 - 1.562 _n_γ = 1.567
2V:
Measured: 60° to 62°, Calculated: 60° to 80°
δ = 0.021
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Chemistry of PolyhaliteHide
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Mindat Formula:
K2Ca2Mg(SO4)4 · 2H2O
Crystallography of PolyhaliteHide
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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)°
Ratio:
a:b:c = 0.999 : 1 : 1.274
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 StructureHide
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| 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 DiffractionHide
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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) |
Geological EnvironmentHide
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Geological Setting:
Oceanic salt deposits; rarely as a volcanic product.
Type Occurrence of PolyhaliteHide
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General Appearance of Type Material:
Geological Setting of Type Material:
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 PolyhaliteHide
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Other Language Names for PolyhaliteHide
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Simplified Chinese:杂卤石
Traditional Chinese:雜鹵石
Common AssociatesHide
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Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat GroupingHide
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Other InformationHide
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Notes:
Soluble in H2O, with precipitation of gypsum and perhaps
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 petrologyHide
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An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for PolyhaliteHide
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References for PolyhaliteHide
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Reference List:
Localities for PolyhaliteHide
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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.
Locality ListHide
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- 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). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.