I think this is what you're asking?
There is an npc in umbala that requires the umbala language quest, as well as doing a short quest after it. Look it up on RMS (i'm at work right now so I can't link it). It essentially lets you turn objects that can create elemental stones into them (example: great natures can be crafted to green lives). It can produce any given amount based on how you choose the numbers. I also believe it lets you craft in reverse, so green lives would become great natures, red bloods to flame hearts. Not 100% on the 2nd part, would need to check it on the char I did the quest with, but I am certain it creates the stones.
There's also an NPC in Amatsu city, in amatsu castle that does the same thing (or even the reverse, again not 100% sure, i'd have to suggest double checking RMS) but it's a greater loss of materials for the finished product.