Hizenite-(Y), Ca₂Y₆(CO₃)₁₁·14H₂O, a new mineral in alkali olivine basalt from Mitsukoshi, Karatsu, Saga Prefecture, Japan

摘要

Hizenite-(Y), ideal formula Ca_(2)Y_(6)(CO_(3))_(11)·14H_(2)O, occurs in druse of alkali olivine basalt at Mitsukoshi, Karatsu, Saga Prefecture, Japan. It occurs as a platy crystal and forms spherical aggregates. Hizenite-(Y) closely associates with lokkaite-(Y), tengerite-(Y), and kimuraite-(Y). It is orthorhombic, a = 6.295(1) ?, b = 9.089(2) ?, c = 63.49(1) ?, V = 3632(1) ?~(3), Z = 4. Hizenite-(Y) is white in color with vitreous to silky luster. The density is 2.98 g/cm~(3) (calc), and there is a perfect cleavage on {001}. The strongest lines in the X-ray powder diffraction pattern are [d (I /I _(0)hkl ] 10.63 (100) 006, 6.384 (77) 0·0·10, 3.962 (51) 0·0·16, 3.821 (27) 029, 1·0·13, 2.060 (23) 306, 0·4·13, 15.57 (20) 004.