Phase relationships in the Er:YbGcli Al-3(BO3)(4)-K2Mo3O10-B2O3-(Gd,ELYb)(2)O-3 (x=0-02, Er-1 at%) system were studied in the temperature range from 1150 to 900 degrees C. Multicomponent melts of 55 mol %K2Mo3O10-45 mol% B2O3 (I) and 55 mol%K2Mo3O10-40 mol% B2O3-5 mol% (Gd,ELYb)(2)O-3 (II) were suggested as reasonable fluxes for high-temperature solution growth of (Yb3+, Er3-):GdAl3(B03)4 single crystals, Yb0.15Gd0.85Al3(BO3)(4) solubility in the complex flux 01 11 composition has been found as varying from 17 to 9.5 mol% with decreasing temperature in the interval of 1000-800 degrees C. As a result, (Er,Yb): GdAB single crystals with high optical quality and sizes up to 20 x 10 x 10 min were grown on dipped "point" seeds. Absorption and stimulated emission spectra, emission lifetimes, and efficiencies of energy transfer from Yb3+ to Er3+ ions were determined. Highly efficient continuous-wave diode-pumped laser operation of (ELYb):GdAl3(BO3)(4) crystal was realized. (C) 2014 Elsevier By. All rights reserved.