Stone is an important resource in The Hobbit: Kingdoms of Middle-earth.
Quarrys increase the stone production of the city, along with boosts from Research in Masonry which allows you to increase stone production by 10% per level.
By conquering Hills your stone production increases by 5%*[level of Hills] conquered.
Stone is needed for the construction of city buildings, buildings and the training of troops. Stone can be protected from attacks by the Vault.