any good farming spots for...

im looking for a NPC that is good for farming weapon upgrade items?

I have yet to see any of these itmes and im as far as Yak's right now in the game.

can someone post a good spot for farming these jewels?

I'm sorry... for farming whatnow?

You're looking for a non-playable-character that is good for farming weapon upgrades?

I'm not following you here...