Re-investigation of ‘minasgeraisite-(Y)’ from the Jaguaraçu pegmatite, Brazil and high-temperature crystal chemistry of gadolinite supergroup minerals

Abstract The chemical composition (including B, Be and Li), the Raman spectrum crystal-structure evolution (at temperature range 27–1000°C) of a Mn-bearing, Bi-rich gadolinite-subgroup mineral from Jaguaraçu Pegmatite, Brazil (type-locality minasgeraisite-(Y)) was studied. Elemental mapping revealed that crystal investigated has complex zonation with various Bi (~8–24 wt.% 2 O 3 ), Ca (~8–10 CaO) Y (~11–17 ) content. sample all specific features minasgeraisite-(Y), except excess and, thus, should be considered as hingganite-(Y). under study bands at 140, 179, 243, 350, 446, 519, 559, 625, 902, 973, 3224, 3353, 3532 3763 cm –1 , is similar to hingganite-(Y) / -(Nd). Crystal-structure refinement confirmed in question line previously obtained data on minerals Pegmatite. High-temperature single-crystal X-ray diffraction studies starts decompose above 800°C. We can conclude beryllosilicates are most stable high-temperature conditions within gadolinite supergroup species higher M -site occupancy have stability upon heating.