Rhabdophane-(Y), YPO₄·H₂O, a new mineral in alkali olivine basalt from Hinodematsu, Genkai-cho, Saga Prefecture, Japan

摘要

Rhabdophane-(Y), ideal formulaYPO_(4)·H_(2)O, occurs in a druse of the Higashimatsuura basalt at Hinodematsu, Genkai-cho, Saga Prefecture, Japan. It occurs as short rod-like crystals and forms radial aggregates. Rhabdophane-(Y) is hexagonal, P 6_(2)22, a = 6.959(2) ?, c = 6.384(2) ?, V = 267.7(1) ?~(3), Z = 3. It is yellowish white to yellowish brown in color with a silky to dull luster. The density is 4.54 g/cm~(3) (calc.). The strongest lines in the X-ray powder diffraction pattern are [d (I /I _(0)) hkl ] 2.821 (100) 102, 3.013 (77) 200, 6.026 (76) 100, 4.385 (47) 101, 3.480 (44) 110, 2.127 (28) 003, and 1.854 (26) 212.