The study of lead borate melt crystallization by differential thermal analysis (DTA) and X-ray diffraction analysis has shown that, for Pb4O(BO3)(2) (or 4PbO center dot B2O3) stoichiometric compound, its well-known orthorhombic modification (non-centrosymmetric Aba2 space symmetry group (SSG), a = 15.472(1), b= 10.802(1), c= 9.9486(6) angstrom unit cell parameters) is metastable. It forms from the undercooled melt and has a melting point of 530 +/- 5 degrees C. (C) 2015 Published by Elsevier B.V.