Carnallite
Species
Uncommon · KMgCl₃·6H₂O
Hydrated potassium magnesium chloride, colourless or reddened by specks of hematite, bitter, and so deliquescent that it dissolves in damp air. One of the last salts to crystallise from an evaporating sea; first described in 1856 from Stassfurt and named for the Prussian mining engineer Rudolf von Carnall. Mined above all for potash fertiliser, and for magnesium: a minor source of it worldwide, but Russia's main one.
Identity
- Formula
- KMgCl₃·6H₂O
- Chemical class
- Halide
- Ore of
- Magnesium
Crystallography
- Crystal system
- Orthorhombic
- Habits
- Granular, Massive, Fibrous
- Fracture
- Conchoidal
Physical properties
- Mohs hardness
- 2.5
- Density
- 1.6 g/cm³
- Luster
- Waxy
- Colors
- colorless, white, light red, yellow
- Transparency
- Transparent, Translucent
Geology
- Origins
- Sedimentary
- Host rocks
- Salt beds
- Associated minerals
- Sylvite, Halite
- Found in
- Evaporite deposit
- Geography
- Germany (Stassfurt), Ukraine (Kalush), Russia (Perm Basin), USA (Carlsbad, New Mexico; Paradox Basin, Utah), Canada (Saskatchewan), Israel and Jordan (Dead Sea)
Classification
- Rarity
- Uncommon
- Gem quality
- No
Sources
- M. Pasero and others, IMA Commission on New Minerals, Nomenclature and Classification, The New IMA List of Minerals, updated September 2026. International Mineralogical Association (CNMNC), 2026.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Carnallite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Carnallite. Wikipedia.
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