Note: The Stone Smeltery cannot be built until you have a level 3 Smeltery (or three level 1 Smelteries, or another equivalent) and have finished the research in the University.. The Stone Smeltery is where the Stone Smelter will smelt cobblestone into stone, stone bricks into cracked stone bricks, clay balls into bricks, clay blocks into terracotta, terracotta into glazed terracotta, all ...