Calcium chloride
Calcium chloride occurs as the rare evaporite minerals sinjarite (dihydrate) and antarcticite (hexahydrate). Another natural hydrate known is ghiaraite - a tetrahydrate. The related minerals chlorocalcite (potassium calcium chloride, KCaCl3) and tachyhydrite (calcium magnesium chloride, Ca Mg2Cl6·12H2O) are also very rare. So is true for rorisite, CaClF (calcium chloride fluoride).