I just wanted to add that I like the idea of things like coins, gems, or gold/silver dust raining from the sky, but since it's magical and would royally disrupt economies in the long run if you could just cart infinite gold from some region I think it would be helpful if that Wealth transmuted into lead or something once it's removed from the sphere of WEALTH magic.
I think transmutation is a good idea. In a wealth area, fruits would turn into gems and coins (and not be edible anymore), but rot and become mouldy the moment they leave the area. Water could be very expensive wine that get's sour when leaving. I think the food ascpect of wealth should not be overlooked. Basically turning an area into the land of milk and honey.