If you run out of tools like delicacies, wooden, or iron
https://ace-wiki.win/index.php/King_of_Avalon_Diamond_Pack_Price_%26_Value_Guide:_500%E2%80%93one_hundred,000_Diamonds_Compared
If you run out of tools like nutrients, wood, or iron, diamonds can be used to buy useful resource packs without delay from the shop.