Hidden Effect
+10% increase to Ice Element Magic Spells
-10% decrease to Wind Element Magic Spells
-2 Avatar Perpetuation Cost for Shiva and Ice Spirit
+2 Avatar Perpetuation Cost for Garuda and Air Spirit
The elemental staves give a 10/15% (NQ/HQ) boost to damage as well as magic accuracy for the corresponding element of the staff. Gravity is a wind based spell so Wind/Auster's Staff would be the best staff to use for that spell.
If you're bursting your Indurations or Distortions with Frost Breath, macro this guy in just before casting to increase the chance of it landing. You just SC'd, so you don't have any TP to lose, macro your sword back in afterwards. Keep in mind you won't get the +10% damage nor will bursting increase the damage any, but the most important thing is to get the spell to actually land unresisted. Unless you like wasting your MP?