So, from what I can piece together...
The god metals result from a body breaking apart from the sheer power of a Shard, and they form the following:
Gas/Spirit Aspect - The willpower and consciousness of the holder, able to be anywhere the atmosphere can spread.
Liquid/Cognitive Aspect - The subconscious and full skill potential of the holder, absorbed easier than water into a human.
Solid/Physical Aspect - The limited, but usable raw material of the holder, in handy bead form.
The ways each of these replenish are rather interesting. The Well of Ascension, for instance. (Please, don't be shy about goofs or overreaching speculation - if I'm wrong, I'm wrong) Magnetic North itself, right? And it was a plug on top of Ruin's spirit aspect, hence Ruin's body had to dribble out through the ground. Why did Preservation collect as a liquid and Ruin as a solid? Why are beads of lerasium bare and atium inside large geodes? Did Preservation merge with the planet's crust?
My theory, yes. The geodes are a protective layer against mutual annihilation of both elements. A magnetic north lerasium well and magnetic south atium well don't quite make sense, as Ruin's mind would not be trapped by the Well. But this may have been the original balance of the planet. The whole thing has so many what-ifs and RAFOs it can make your head spin. But this raises the curious possibility of what the south polers may have been doing when faced with the scientific curiosity of a world where the north and south poles may have both been on the opposite side of the planet.