YBCO single crystals 1-2-3 were grown from a melted mixture of YBa2Cu3O7-y-BaO-CuO using the method of horizontally directed cooling in the zone melting equipment. This method makes it possible to grow high quality single crystals with dimensions up to 3*2*0.15 mm3, which may then be extracted simply from the crucible. Differences in superconducting properties, parameters of crystal structure and the microstructure were found in single crystals grown in Al2O3 and ZrO2 crucibles. It is possible that these differences are connected with the different stability of the crucibles used and consequently with the presence of impurities in the melted charge during the single crystal growth process.