In recent years, despite significant progress in the development of new methods for the synthesis of diamond crystals and in their post-growth treatment, many questions remain unclear about the conditions for the formation and degradation of aggregate impurity nitrogen forms. Meanwhile, they are very important for understanding (evaluating) the origin, age, and post-growth conditions of natural diamonds. In the present work, an attempt was made to analyze the causes of the formation of high concentrations of N3V centers in natural IaB-type diamonds from the Kholomolokh placer (the Northeast Siberian craton). The possibility of decay of B centers during the plastic deformation of diamonds is analyzed and experiments on the high-temperature annealing of diamonds containing B centers are reported. The formation of N3V centers during the destruction of the B centers at high-pressure annealing of crystals has been established by experiment. It is assumed that, in the post-growth period, diamond crystals were exposed to tectono-thermal stages of raising the superplumes of the Earth's crust of the Siberian craton.