Zippeite

Zippeite is a hydrous potassium sulfate O ). It forms yellow to reddish brown monoclinic -prismatic crystals with perfect cleavage. The typical form is as encrustations and pulverulent earthy masses. It forms as efflorescent encrustations in underground uranium mines. It has a Mohs hardness of 2 and a specific gravity yellow in UV radiation and is a radioactive mineral.