Iron Stone

Quick question, what do I do with the Iron Stone?

You have to upgrade an item past a certain level. "Upgrades of up to 100 levels for Legendary equipment, 80 for Epic, 60 for Rare, 40 for Magic and 20 for Normal are possible." The the upgrade button becomes break and you can use your stones to break the limit. Different stones for different types of weapons. More Info: https://game.nanoo.so/darksword/forum/455641?code=5b709c13b17d29f4369768de22e5ed68