(OFZ) technique. The crystals were grown at relatively high growth rates of 4 mm h -1 to minimize In2O3 evaporation during the growth process, starting from raw powders of (Gd3-xREx)In2Ga3O12 synthesized via conventional solid-state method. In the initial trials, we observed significant Indium oxide evaporation and encountered challenges in stabilizing the melt zone. To address this problem, a mixed gas flow of Ar (80 ml/min) and O2 (20 ml/min) was applied along with the introduction of an auxiliary pressure of 6 bar in the glass chamber in which the process takes place. Additionally, an excess of 5% of In2O3 was used to compensate for the reduced evaporation at the relatively high process temperatures. This approach effectively stabilized the melt zone and minimized In2O3 evaporation. The compounds crystallize in a cubic garnet structure with space group 𝐼𝑎3 ̅ 𝑑 (no. 230), with the substituents well incorporated in accordance with Vegard's law. BSE imaging and EDX analysis reveal homogeneous elemental distributions within each crystal. The high quality of the single crystals is further evidenced by their photoluminescence properties, which display the characteristic narrow-line 4f n ↔︎ 4f n transitions of the incorporated lanthanoid ions Nd 3+