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

Hizenite-(Y), ideal formula Ca₂Y₆(CO3)₁₁·14H₂O, 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) Å, b = 9.089(2) Å, c = 63.49(1) Å, V = 3632(1) ų, Z = 4. Hizenite-(Y) is white in color with vitreous to silky luster. The density is 2.98 g/cm3 (calc), and there is a perfect cleavage on {001}. The strongest lines in the X-ray powder diffraction pattern are [d (I/I₀)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.