A weapon question.

So, here's the thing: I bought a weapon on Mount Gagazet (sp?) for Rikku by O'aka's brother Wantz or something like that. I don't remember the name of the weapon, but what's interesting is that this weapon has an ability called Alchemy and I can't figure out what that certain ability does, so if one of you guys in here could please elaborate that would be really nice :) Thanks.

it doubles the potency of recory items

so i think this means... like if a high potions gives 1k health, that would make it 2k