IR-microspectroscopy was used to investigate gem quality cubic diamonds from placers of NE Siberia. The studied diamonds contain not only main À-, Ñ-defects and, in some cases, B-defects, but also relatively rare centers X (N+ ion), and Y [Hainschwang et al., 2012], peaks in the 1350-1380 ñm-1 range, and various types of Amber centers. Integral spectra suggest that nitrogen concentration in these diamonds is relatively low: 60-265 ppm. Micro-IR investigation revealed highly heterogeneous nitrogen distribution in all the crystals. The general trend consists of gradual decrease of total N concentration and of A-defects fraction from growth center towards periphery; N concentration in the center may reach 990 ppm, being much higher than the average value. In peripheral zones the Ñ-, Y-, Õ-, and Amber centers appear. Their presence indicate short duration of post-growth annealing period.