The Deep Queen's Diamond

This small blue gem is all that remains of Umberlee, Goddess of the Sea.
You may make a DC 15 Religion check. On a success roll a d100. If you roll over your level you may cast one of the following:Water Walk, Water Breathing, Control Water, Tidal Wave. If you roll below it cast Tidal wave centered on yourself. On
a failure the gem loses its power for 8 hours.
This ability may only be used once every 3 days.