Barioperovskite, BaTiO_3, a new mineral from the Benitoite Mine, California

Abstract

Barioperovskite, ideally BaTiO_3, is a new member of the perovskite group. It is found as micro- to nano-crystals in a host of amorphous material contained within hollow, tubular inclusions in benitoite from the Benitoite Mine, San Benito County, California, U.S.A. The mean chemical composition determined by electron-microprobe analysis is (wt%) BaO 65.46, TiO_2 34.57, SiO_2 0.89, sum 100.92. The empirical formula calculated on the basis of 3 O is Ba_(0.97)Ti_(0.98)Si_(0.03)O3. Barioperovskite is orthorhombic, Amm2; a = 3.9874 Å, b = 5.6751 Å, c = 5.6901 Å, V = 128.76 Å3, and Z = 2. The electron backscattered diffraction pattern is an excellent match to that of synthetic BaTiO_3 with the Amm2 structure. The strongest calculated X-ray powder diffraction lines from the synthetic BaTiO_3 data are [d in Å, (I), hkl] 4.018 (18) (011), 2.845 (30) (002), 2.830 (100) (111), 2.316(20) (102), 2.312 (23) (120), 2.009 (28) (022), 1.640 (17) (113), 1.637 (19) (131), 1.633 (18) (202), and 1.415 (15) (222). The mineral is named after its composition, a Ba-dominant member of the perovskite group.

Additional details