Farneseite is a mineral from the cancrinite group with 14 layer stacking. It is a complex silicate mineral with formula (Na,Ca,K) 56(Al 6Si 6O 24) 7(SO 4) 12·6H2O. It was named after a location in Farnese, Lazio , Italy. It is a member of the cancrinite group, approved in 2004 as a new mineral species. The group is characterized by the number of stacking layers making up each member, with farneseite being one of newest minerals in the group with a 14 layer stacking structure. It is a clear transparent mineral and has a hexagonal crystal system with crystal class of 6/m and space group of P63/m. The specimens discovered in Farnese were in a pyroclastic rock from the Làtera Cauldera
In the volcanic region of Latium, Italy, a few scientists found some crystals with hexagonal morphology while doing a study of the cancrinite-group minerals. These crystals were in a rock sample they had collected from a small village called Farnese in the Viterbo Province, north of Rome. They believed the substance to be sacrofanite , but after several diagnostic tests they observed the powder IR spectrum of the sample showed some differences from sacrofanite. They then performed a complete chemical and structural analysis which confirmed that the substance indeed was a new feldspathoid species related to the cancrinite-sodalite group. The cancrinite group are minerals with hexagonal and trigonal crystal systems with various anions and cations located in cages within the main frame. The crystal structures of the members of the group are characterized by the six membered rings of SiO4 and Al04 tetrahedra. The layers are lined up along the c axis in the ABCABABACBACAC… fashion.