CoCl2 (blue) + 6H2O (light red/pink) = CoCl2 6H2O, anhydrous cobalt chloride is transparent blue, after absorbing moisture, it becomes light red/pink color, and can be decomposed into cobalt chloride for reuse under heating. Blue silica gel desiccant is widely used in precision instruments, leather, shoes, clothing, food, medicine and household appliances.