When 80 stones are placed on a stockpile, they will turn into four 2 x 1 stone bricks.

Stones can be naturally harvested from groups of Stone Boulders using the Harvest task.

Stone can be obtained with the Tunnel task, Quarry task or Harvest task on Boulders. It can also be obtained with the Cleaning task over corpses of Corruptrons and Bricktrons.

This is the only renewable resource in the game.