What is "picromerite"

n. (context mineralogy English) A saline evaporite, consisting of a mixed potassium and magnesium sulphate, with the chemical formula potassium₂magnesium(sulfuroxygen₄)₂·6(water).

Picromerite (synonyms: schoenite, schönite) is a mineral from the class of hydrous sulfates lacking additional anions, and containing medium to large cations according to the Nickel-Strunz classification.