[en] This paper is concerned with growth defects (dislocations, lineage structure, twins, splitting, block-construction, cracks) occurring in crystallization by the Verneuil method. This study is stimulated by a demand in high quality crystal nucleus. Each crystal nucleus is from 6 to 8 mm in diameter and to 20 mm long. It is shown that in the case of YFeO₃ the dislocation density reaches a maximum of about 10⁵ cm^-2 near the crystal nucleus periphery, while its center is practically free of dislocations. It has been found that twinning is typical for the substantial crystal growth in any direction normal to <001>, in particular <110>