Advanced fabrials are created using several different techniques. Conjoined fabrials require a careful division of the gemstone—and the spren inside. If performed correctly, the two halves will continue to behave as a single gemstone. Note that rubies and flamespren are traditional for this purpose— as they have proven the easiest to divide, and the quickest in response times. Other types of spren do not split as evenly, as easily, or at all. —Lecture on fabrial mechanics presented by Navani Kholin to the coalition of monarchs, Urithiru, Jesevan, 1175
