A laboratory is a building that allows commanders in the province to do magic-related things. In particular, a lab is required for:

1. Research
2. Casting rituals
3. Forging items
4. Transferring gems and items to/from the national treasury (though commanders can still trade gems and items between each other without a lab)
5. Recruiting mages (anything with elemental or sorcery Magic paths)

Labs can be built by any mage. They cost 500g (Arcosephale pays 250g) and remain if a province changes hands.