Selsurt) loparite with average composition ([Na.sub.0.45] [LREE.sub.0.35] [Ca.sub.0.14] [Sr.sub.0.04] [Fe.sub.0.005] [Th.sub.0.004])([Ti.sub.0.90] [Nb.sub.0.10] [Ta.sub.0.008])[O.sub.3] and average molecular weight of 172, classified as calcian niobian loparite-(Ce), is actually a solid solution of loparite ([Na.sub.0.5] [LREE.sub.0.5] Ti[O.sub.3]) with perovskite (CaTi[O.sub.3]) and tausonite (SrTi[O.sub.3]) in the thorium-substituted A-site and with lueshite
(NaNb[O.sub.3]) in the tantalum-substituted B-site.
Associated minerals are: aegirine, arfvedsonite, eudialyte, potassic feldspar, sodalite, albite, carbonate-fluorapatite, lueshite
, natrolite, and tuperssuatsiaite.
Oxides & Hydroxides Anatase Birnessite Doyleite Franconite Gibbsite Goethite Hematite Hochelagaite Lueshite Todorokite Woodruffite VUK3
Lueshite, a rare perovskite-group mineral (Safiannikoff, 1959), is extremely rare and is known from only a single specimen from a miarolitic cavity.