What do I need magic ore for?

The magic ore can be used to help your citizens, to make orders in Builder's House, Stonemason Dwarf's Hut, Foundry of Ferrous Metals, Gem Cutter's Workshop, Foundry of Commodities, Greenhouse, Wizard's Tower and some other craft buildings. You'll also need it to finish some of the quests, upgrade the buildings, the Castle and the capacity of Storage.