Terpene cyclase that catalyzes the cyclization of farnesyl diphosphate (FPP) to various sesquiterpenes, including beta-elemene, viridiflorene and gamma-cadinene (PubMed:32233445). Gamma-cadinene is the major product of PILCRDRAFT_825684 (PubMed:32233445). (2E,6E)-farnesyl diphosphate = diphosphate + viridiflorene The DDXXD motif is important for the catalytic activity, presumably through binding to Mg(2+). Belongs to the terpene synthase family.