In this paper, we suggest the synthetic routes to prepare octahedrally crystallized hematite particles. One of these routes allows stabilizing pseudomorphic nanoparticles. Calcination of iron (III) oleate at 300 °C in air gives triangular shaped magnetite particles. At higher temperatures (400–500 °C), the octahedrons, about 1 μm in size, with predominant hematite phase are obtained. Calcination of the same precursor in the presence of polymeric beads results in a decrease of particle size up to 20 nm while preserving the magnetic phase admixture. To achieve effective stabilization, swelling of polystyrene beads during the iron (III) oleate impregnation is required.