stone is the resource to upgrade walls it replace gold and exlier
new wall cost
lvl Cost (stone) 1 20 2 100 3 500 4 1,000 5 3,000 6 7,500 7 20,00 8 50,000 9 100,000 10 300,000 11 400,000
stone quarry (produce stones):
Level Build Cost (gold) Capacity Production Per Hour Town Hall Level Required 1 2,000 250 10 2 2 5,000 300 20 3 3 10,000 400 30 4 4 30,000 840 45 5 5 50,000 1,280 60 6 6 100,000 1,800 80 7 7 200,000 2,200 100 8 8 400,000 2,500 200 9 9 800,000 3,000 400 10
Edit: decrease the gold cost
stone storage (coming soon...)

