Kainite

[kainait]

(noun.) a white mineral consisting of magnesium sulphate and potassium chloride; a source of potassium salts; used as a fertilizer.

Typed by Leona--From WordNet

(n.) A compound salt consisting chiefly of potassium chloride and magnesium sulphate, occurring at the Stassfurt salt mines in Prussian Saxony.

Checker: Michelle

n. a hydrated compound of the chlorides and sulphates of magnesium and potassium used as a fertiliser.

Checker: Rene