The chemical composition (including B, Be, Li), the Raman spectrum and the crystal structure evolution (at the temperature range 27-1000 °C) of Mn-bearing, Bi-rich gadolinite subgroup mineral from the Jaguaraçu Pegmatite, Brazil (type-locality of minasgeraisite-(Y)) was studied. Elemental mapping revealed that the crystal being investigated has complex chemical zonation with various Bi (~8-24 wt.% Bi2O3), Ca (~8-10 wt.% CaO) and Y (~11-17 wt.% Y2O3) content. The sample in hand has all specific features of the chemical composition of minasgeraisite-(Y), except Ca excess and, thus, should be considered as hingganite-(Y). The Raman spectrum of the sample under study consists of the number of bands (140, 179, 243, 350, 446, 519, 559, 625, 902, 973, 3224, 3353, 3532 and 3763 cm -1 ) and is similar to that of hingganite-(Y) / -(Nd). Crystal structure refinement confirmed that the crystal in question should be considered as hingganite-(Y) and is in line with the previously obtained data on gadolinite subgroup minerals from the Jaguaraçu Pegmatite. High-temperature single crystal X-ray diffraction studies revealed that the mineral starts to decompose above 800 °C. We can conclude that beryllosilicates are most stable at high-temperature conditions within the gadolinite supergroup and that species with a higher M-site occupancy have higher stability upon heating.