Yttrialite and abukumalite from a pegmatite of Suisho-yama, Iizaka Village, Fukushima Prefecture

Abstract

Yttrialite and abukumalite were collected from pegmatite in Iizaka Village, Fukushima Prefecture. Yttrialite has G 4.560 and n 1.7604. The result of chemical analysis is given in Table I (No. 2). Powder photograph gives a cubic unit cell a 10.532 A, its crystal structure like that of pyrochlore, koppite and atopite. The cubic yttrialite may be a metamict state. Abukumalite has G 4.567. Its bulk analysis is given in Table IV (No. 2). Powder photograph of abukumalite shows close agreement with that of apatite from Drango, Mexico and their data yield a 9.58 A, c 6.81 A for abukumalite, compared with a 9.51 A, c. 6.77 A for apatite.