Transient regions between iron oxide crystalline phases were found in various stages of α-Fe₂O₃ structural-chemical transformation into FeO by Moessbauer spectroscopy. Particle sizes in those regions are less than 8 nm. The sequence of phase transformations was established for α-Fe₂O₃ reduction to iron at temperatures higher and lower than the wustite stability point (approximately 570 °C). Two phases Fe_1-xO and FeO were found to form upon the reduction within the wustite stability region (the stoichiometric phase is formed first). It was shown that reduction of hematite into magnetite occurs within temperature range 570-600 °C by the multistage mechanism, while magnetite reduction to wustite occurs by a zonal mechanism, where three phases Fe₃O₄, FeO and Fe are present in a sample simultaneously.