Hydrated sulphate containing halogen
Specific gravity: 2.15
Hardness: 2½ to 3
Colour: Colourless; yellow, brownish, greyish-green, red, violet, blue; colourless in transmitted light
Kainite is a secondary mineral formed only in marine evaporite potash
deposits, often as a result of subsequent metamorphism, associated with sylvite,
langbeinite and picromerite
The type locality, Leopoldshall, Stassfurt Potash deposit, Saxony-Anhalt, Germany, is a potash deposit of oceanic origin (Mindat).
At the Carlsbad Potash Mining District, Eddy county, New Mexico, USA, kainite occurs in potash deposits associated with sylvite and langbeinite (Dana).
Kainite is decomposed by water into epsomite and sylvite (Mindat).
KMg(SO4)Cl.3H2O + 4H2O → Mg(SO4).7H2O + KCl
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