All gemstones leak Stormlight at a slow rate—but so long as the crystal structure remains mostly intact, the spren cannot escape. Managing this leakage is important, as many fabrials also lose Stormlight through operation. All of this is tied up in the intricacies of the art. As is understanding one last vital kind of spren: logicspren. —Lecture on fabrial mechanics presented by Navani Kholin to the coalition of monarchs, Urithiru, Jesevan, 1175
