Although I'm personally stuck since there's no realistic way of getting 'infinity' soulstones, I can say that you can get the following things by:
Soulstone: Killing the last enemy over and over, it doesn't seem to get any stronger as you kill it.
Infinity/singularity: They are one and the same, except that w/e infinities you got transform into singularities when you destroy the heart.
Infinites are basically you getting a Quintilian of any resource, with it counting up to (I think) 16 times for all resources other than flint and fiber. You can get 16 singularities per reset if you max out all resources other than those two.
It's pretty hard to get more than the food infinity for the first reset unless you are super determined, this 1 singularity can be used to get the ability automatically spend the proper amount of various resources to get w/e you click on, assuming you have enough. This allows you to keep maxing out masons without having to go through the whole ordeal of getting all the right resources to make up for it.