This silica gel is a bead or granule that has been washed with a concentration of cobalt chloride (a heavy metal salt). The cobalt chloride is a deep-blue color when dry and turns from blue to pink as it becoAmes saturated
Blue silica gel has cobalt chloride, which allows the blue silica gel change its color to pink when it reached its maximized adsorption capacity. Once pink it can be reactivated with heat to dry out the moisture