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The mineralogy of Potassium

General Properties
Symbol:	K
Atomic Number:	19
Standard atomic weight (A_r):	39.0983(1)
Electron configuration:	[Ar] 4s¹

Photos

<	Potassium pearls under paraffin oil	>

Atomic Properties
Electronegativity (Pauling scale):	0.82
Atomic Radius:	243 pm
Ionic Radius:	138 pm (+1)
Van der Waals Radius:	275 pm
1st Ionization energy:	419 kJ/mol
1st Electron affinity:	-48 kJ/mol
Oxidation States:	1

Physical Properties
Standard State:	solid
Bonding Type:	metallic
Melting Point:	337 K
Boiling Point:	1032 K
Density:	0.86 g/cm³
Metal/Non-Metal:	alkali metal

Main isotopes of Potassium
Isotope	% in Nature	Half Life	Decay type	Decay product
³⁹K	93.26%	stable
⁴⁰K	0.012%	12.48(3)×10⁹y	β−	⁴⁰Ca
			ε	⁴⁰Ar
			β+	⁴⁰Ar
⁴¹K	6.73%	stable

Main ions of Potassium
Name	Ion	Example minerals
potassium	K⁺	Sylvite, Niter

Other Information
Year Discovered:	1807
Discovered By:	Humphry Davy
Year Isolated:	1807
Isolated By:	Humphry Davy
Named For:	from the English word "potash"
CPK color coding:	#8F40D4
External Links:	Wikipedia WebElements Los Alamos National Laboratory Theodore Gray's PeriodicTable.com

Simple Compounds and Mineral Names
Sulfides	dipotassium sulphide	K₂S	+1
	dipotassium disulphide	K₂S₂	+1
	dipotassium hexasulphide	K₂S₆	+1
	dipotassium trisulphide	K₂S₃	+1
	dipotassium pentasulphide	K₂S₅	+1
	dipotassium tetrasulphide	K₂S₄	+1
Selenides	dipotassium selenide	K₂Se	+1
Tellurides	dipotassium telluride	K₂Te	+1
Hydrides	potassium hydride	KH	+1
Hydroxides	potassium hydroxide	KOH	+1
Fluorides	potassium fluoride	KF	+1	Carobbiite
Chlorides	potassium chloride	KCl	+1	Sylvite
Iodides	potassium iodide	KI	+1
Oxides	dipotassium oxide	K₂O	+1
	potassium superoxide	KO₂	+1
	dipotassium peroxide	K₂O₂	+1
Carbonates	potassium carbonate	K₂CO₃	+1
Nitrates	potassium nitrate	KNO₃	+1	Niter
Sulfates	potassium sulfate	K₂SO₄	+1

Mineral Diversity of Potassium
2. Sulfides And Sulfosalts	10 valid mineral species
3. Halides	34 valid mineral species
4. Oxides	25 valid mineral species
5. Carbonates	11 valid mineral species
6. Borates	8 valid mineral species
7. Sulfates	88 valid mineral species
8. Phosphates, Arsenates, Vanadates	66 valid mineral species
9. Silicates	256 valid mineral species
10. Organic Compounds	4 valid mineral species
Total:	502 valid species containing essential Potassium

Geochemistry of Potassium
Goldschmidt classification:	Lithophile
K⁺ enters later phases in igneous rocks due to its large size.
K⁺ is one of the eight most abundant solutes in average river water.
K⁺ solute can be a limiting nutrient in the growth of bacteria.
K⁺ solute is a macronutrient on land.
K⁺ is essential to nutrition of at least some vertebrates ('essential minerals').

Elemental Abundance for Potassium
Crust (CRC Handbook)	2.09 x 10^-2	mass fraction, kg/kg
Crust (Kaye & Laby)	1.7 x 10^-2	mass fraction, kg/kg
Crust (Greenwood)	1.8400 x 10^-2	mass fraction, kg/kg
Crust (Ahrens/Taylor)	9.100 x 10^-3	mass fraction, kg/kg
Crust (Ahrens/Wänke)	1.7600 x 10^-2	mass fraction, kg/kg
Crust (Ahrens/Weaver)	1.7000 x 10^-2	mass fraction, kg/kg
Upper Crust (Ahrens/Taylor)	2.8000 x 10^-2	mass fraction, kg/kg
Upper Crust (Ahrens/Shaw)	2.5700 x 10^-2	mass fraction, kg/kg
Sea Water (CRC Handbook)	3.99 x 10^-4	mass per volume fraction, kg/L
Sea Water (Kaye & Laby)	3.9 x 10^-4	mass per volume fraction, kg/L
The Sun (Kaye & Laby)	3.7 x 10^-3	atom mole fraction relative to Si=1
Solar System (Kaye & Laby)	3.8 x 10^-3	atom mole fraction relative to Si=1
Solar System (Ahrens)	3.77 x 10^-3 (7.7%)	atom mole fraction relative to Si=1 (% uncertainty)

Element association of Potassium in the Mineral World
This table compares the known valid mineral species listed listed with Potassium and the other elements listed based on the official IMA formula. Note that unlike other sections on this page this includes non-essential elements. The first data column contains the total number of minerals listed with Potassium and the element listed for that row. The second data column lists this number as a percentage of all minerals listed with Potassium. The final data column compares this percentage against the percentage of all minerals that contain the element listed in each row. Click on a heading to sort.

Element	Valid Minerals listed with element and Potassium	% of K minerals	Relative to % in all minerals
Oxygen	577 minerals with K and O	95.21%	17.23% higher
Hydrogen	385 minerals with K and H	63.53%	13.05% higher
Silicon	332 minerals with K and Si	54.79%	97.59% higher
Sodium	258 minerals with K and Na	42.57%	123.19% higher
Aluminium	208 minerals with K and Al	34.32%	70.18% higher
Calcium	193 minerals with K and Ca	31.85%	25.77% higher
Iron	144 minerals with K and Fe	23.76%	3.82% higher
Sulfur	129 minerals with K and S	21.29%	3.28% lower
Magnesium	98 minerals with K and Mg	16.17%	17.71% higher
Titanium	87 minerals with K and Ti	14.36%	101.93% higher
Chlorine	79 minerals with K and Cl	13.04%	75.98% higher
Fluorine	76 minerals with K and F	12.54%	55.39% higher
Manganese	69 minerals with K and Mn	11.39%	4.31% lower
Copper	53 minerals with K and Cu	8.75%	35.64% lower
Phosphorus	51 minerals with K and P	8.42%	32.11% lower
Barium	47 minerals with K and Ba	7.76%	67.74% higher
Niobium	42 minerals with K and Nb	6.93%	127.28% higher
Lithium	32 minerals with K and Li	5.28%	161.17% higher
Arsenic	32 minerals with K and As	5.28%	59.20% lower
Uranium	31 minerals with K and U	5.12%	0.75% lower
Carbon	25 minerals with K and C	4.13%	49.30% lower
Vanadium	24 minerals with K and V	3.96%	17.60% lower
Zinc	24 minerals with K and Zn	3.96%	30.73% lower
Zirconium	23 minerals with K and Zr	3.80%	57.94% higher
Boron	22 minerals with K and B	3.63%	27.94% lower
Nitrogen	21 minerals with K and N	3.47%	35.78% higher
Strontium	20 minerals with K and Sr	3.30%	18.54% higher
Beryllium	18 minerals with K and Be	2.97%	34.76% higher
Lead	18 minerals with K and Pb	2.97%	71.86% lower
Yttrium	9 minerals with K and Y	1.49%	36.44% lower
Chromium	8 minerals with K and Cr	1.32%	27.58% lower
Caesium	8 minerals with K and Cs	1.32%	156.96% higher
Cerium	8 minerals with K and Ce	1.32%	58.29% lower
Molybdenum	7 minerals with K and Mo	1.16%	24.24% lower
Tantalum	5 minerals with K and Ta	0.83%	31.80% lower
Selenium	5 minerals with K and Se	0.83%	68.69% lower
Antimony	4 minerals with K and Sb	0.66%	88.22% lower
Thorium	4 minerals with K and Th	0.66%	5.17% lower
Tungsten	3 minerals with K and W	0.50%	44.68% lower
Thallium	3 minerals with K and Tl	0.50%	67.17% lower
Rubidium	3 minerals with K and Rb	0.50%	397.85% higher
Tin	3 minerals with K and Sn	0.50%	73.80% lower
Nickel	3 minerals with K and Ni	0.50%	85.57% lower
Cadmium	2 minerals with K and Cd	0.33%	37.77% lower
Tellurium	2 minerals with K and Te	0.33%	90.43% lower
Bismuth	2 minerals with K and Bi	0.33%	92.07% lower
Iodine	2 minerals with K and I	0.33%	37.77% lower
Lanthanum	1 mineral with K and La	0.17%	88.29% lower
Scandium	1 mineral with K and Sc	0.17%	56.71% lower
Bromine	1 mineral with K and Br	0.17%	44.68% lower
Silver	1 mineral with K and Ag	0.17%	95.69% lower

Periodic Table

2He

3Li

4Be

Show/hide current element

Default Categories CPK Electronegativity Atomic Radius Lowest Oxidation Highest Oxidation Crustal Abundance Goldschmidt Mineral Species Minerals with K Relative Frequency

Argon << Potassium >> Calcium

Most widespread minerals containing Potassium
This list of minerals containing Potassium is built from the mindat.org locality database. This is based on the number of localities entered for mineral species and is therefore slanted towards minerals interesting to collectors with less coverage of common rock-forming-minerals so it does not give an undistorted distribution of Potassium mineral species. It is more useful when comparing rare species rather than common species.

Most widespread minerals containing Potassium

This list of minerals containing Potassium is built from the mindat.org locality database. This is based on the number of localities entered for mineral species and is therefore slanted towards minerals interesting to collectors with less coverage of common rock-forming-minerals so it does not give an undistorted distribution of Potassium mineral species. It is more useful when comparing rare species rather than common species.

Name	Formula	Crystal System	Mindat Localities
Muscovite	KAl₂(AlSi₃O₁₀)(OH)₂	Monoclinic	21300
Microcline	K(AlSi₃O₈)	Triclinic	6104
Phlogopite	KMg₃(AlSi₃O₁₀)(OH)₂	Monoclinic	3151
Orthoclase	K(AlSi₃O₈)	Monoclinic	3071
Jarosite	KFe³⁺₃(SO₄)₂(OH)₆	Trigonal	2781
Nepheline	Na₃K(Al₄Si₄O₁₆)	Hexagonal	1724
Carnotite	K₂(UO₂)₂(VO₄)₂ · 3H₂O	Monoclinic	1315
Alunite	KAl₃(SO₄)₂(OH)₆	Trigonal	1279
Sanidine	K(AlSi₃O₈)	Monoclinic	983
Cryptomelane	K(Mn⁴⁺₇Mn³⁺)O₁₆	Monoclinic	692

Photos
Muscovite Zé Pinto claim, Aldeia, Cuparaque, Minas Gerais, Brazil Microcline Kashmal pegmatites, Shigar Valley, Shigar District, Gilgit-Baltistan, Pakistan Phlogopite, etc. Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar Orthoclase Formazza Valley, Verbano-Cusio-Ossola Province, Piedmont, Italy Muscovite Zé Pinto claim, Aldeia, Cuparaque, Minas Gerais, Brazil Microcline Kashmal pegmatites, Shigar Valley, Shigar District, Gilgit-Baltistan, Pakistan Phlogopite, etc. Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar Orthoclase Formazza Valley, Verbano-Cusio-Ossola Province, Piedmont, Italy Muscovite Zé Pinto claim, Aldeia, Cuparaque, Minas Gerais, Brazil Microcline Kashmal pegmatites, Shigar Valley, Shigar District, Gilgit-Baltistan, Pakistan Phlogopite, etc. Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar Orthoclase Formazza Valley, Verbano-Cusio-Ossola Province, Piedmont, Italy

Photos

Muscovite

Zé Pinto claim, Aldeia, Cuparaque, Minas Gerais, Brazil

Microcline

Kashmal pegmatites, Shigar Valley, Shigar District, Gilgit-Baltistan, Pakistan

Phlogopite, etc.

Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar

Orthoclase

Formazza Valley, Verbano-Cusio-Ossola Province, Piedmont, Italy

Muscovite

Zé Pinto claim, Aldeia, Cuparaque, Minas Gerais, Brazil

Microcline

Kashmal pegmatites, Shigar Valley, Shigar District, Gilgit-Baltistan, Pakistan

Phlogopite, etc.

Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar

Orthoclase

Formazza Valley, Verbano-Cusio-Ossola Province, Piedmont, Italy

Muscovite

Zé Pinto claim, Aldeia, Cuparaque, Minas Gerais, Brazil

Microcline

Kashmal pegmatites, Shigar Valley, Shigar District, Gilgit-Baltistan, Pakistan

Phlogopite, etc.

Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar

Orthoclase

Formazza Valley, Verbano-Cusio-Ossola Province, Piedmont, Italy

Localities with greatest number of different Potassium mineral species

1	Arsenatnaya fumarole, Second scoria cone, Northern Breakthrough (North Breach), Great Fissure eruption (Main Fracture), Tolbachik Volcanic field, Milkovsky District, Kamchatka Krai, Russia	46 K minerals
2	Poudrette quarry (De-Mix quarry; Demix quarry; Uni-Mix quarry; Carrière Mont Saint-Hilaire; MSH), Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada	43 K minerals
3	Mount Vesuvius, Somma-Vesuvius Complex, Naples, Campania, Italy	40 K minerals
4	Kukisvumchorr Mt, Khibiny Massif, Murmansk Oblast, Russia	35 K minerals
5	Dara-i-Pioz Massif, Districts of Republican Subordination, Tajikistan	31 K minerals
	Vesuvius fumaroles, Mount Vesuvius, Somma-Vesuvius Complex, Naples, Campania, Italy	31 K minerals
7	Koashva Open Pit, Koashva Mt, Khibiny Massif, Murmansk Oblast, Russia	30 K minerals
8	Yadovitaya fumarole, Second scoria cone, Northern Breakthrough (North Breach), Great Fissure eruption (Main Fracture), Tolbachik Volcanic field, Milkovsky District, Kamchatka Krai, Russia	27 K minerals

Spotted a mistake/omission? - These pages are a work in progress, so please send all comments/corrections to jolyon@mindat.org. Thank you.

Constants and physical property data from:

David R. Lide (ed.), CRC Handbook of Chemistry and Physics, 85th Edition. CRC Press. Boca Raton, Florida (2005).
Kaye and Laby Tables of Physical & Chemical Constants (2005). Section 3.1.3, Abundances of the elements
A. Earnshaw, N. Greenwood, Chemistry of the Elements, 2nd edition, Butterworth-Heinemann, (1997)
Thomas J. Ahrens (ed.), Global Earth Physics : A Handbook of Physical Constants, American Geophysical Union (1995)
L.B. Railsback, An Earth Scientist's Periodic Table of the Elements and Their Ions : Geology 31:9 p737-740 (2003)
Emsley, J. Nature's Building Blocks: An A-Z Guide to the Elements. New York: Oxford University Press (2001)

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