Transient regions between iron oxide crystalline phases were found in various stages of alpha -Fe2O3 structural-chemical transformation into FeO by Mossbauer spectroscopy. Particle sizes in those regions are less than 8 nm. The sequence of phase transformations was established for alpha -Fe2O3 reduction to iron at temperatures higher and lower than the wustite stability point (similar to 570 degreesC). Two phases Fe1-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 degreesC 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. O 2000 Elsevier Science B.V. All rights reserved.