The phase composition change as a result of the solid-phase carbothermal reduction of metal from a bulk complex oxide with a low iron content-dunite was explained. The experiments were conducted in a laboratory resistance furnace (Tamman's furnace) to study solid-phase carbothermal reduction of iron from dunite at temperature 1300 °C and for 1 hour holding time. A comparison of the results of the micro-X-ray and X-ray phase analysis of the initial dunite samples with samples after the solid-phase carbothermal reduction was performed. The phases in the initial samples of dunite were: