There's no pvp power JC only gems! As far as i can tell even 320 PvP power gems are far superior to even 320int.
4818/1818=2.65* PvP power per 0.1%
Just 265 pvp power per 1% more damage (I realise theres a slight Diminshing return but i doubt it will pass one 320 gem not giving 1% damage).
I could be wrong but getting 1% more damage also could be thought as 1% more intellect since it will be scaling the damage with your spellpower. Jewelcrafters need these gems... or I'm going to have to go blacksmithing on a warlock for a bonus 640 PvP power ¬_¬