You target a spell currently in effect that has a duration of 1 minute or greater from time of its casting. The targeted spell becomes immune to the effects of the spell Dispel Magic. This immunity ends if the diamond used as the material component for this spell is destroyed or stops existing or is otherwise no more. The same diamond can be used for multiple castings of this spell and all immunity granted remains until the diamond is no more. The immunity also ends if the targeted spell ends by another means - such as duration expiring. 

The effect of this spell, Dispel Immunity, cannot be dispelled.