Kurzick/Luxon Faction - What is it for?

Ok, I know you can give faction to your alliance in order to improve their standing within the faction so they can hold a city or outpost...
But you can also redeem it for other things. My question simply is... what rewards can you get for faction?

For 1,000 Kurzick or Luxon faction, you can get Jadeite or Amber (respectively) by redeeming it at the [Faction Rewards] NPC.

Where is this NPC?