In this study, nanocrystalline Fe25Se75 powders were synthesized by high-energy mechanical alloying (MA) for milling times up to 52 h. The evolution of the crystalline structure, hyperfine parameters, and magnetic behavior was investigated using Mossbauer spectroscopy (MS), vibrating sample magnetometry (VSM), and X-ray diffraction (XRD). The Mossbauer spectra of samples milled up to 33 h showed a dominant paramagnetic doublet, corresponding to the formation of the FeSe2 phase, alongside a sextet from residual alpha-Fe. However, after 52 h of milling, the spectra showed the emergence of a broad ferromagnetic sextet, indicating a phase transformation from paramagnetic FeSe2 to ferromagnetic Fe7Se8. This magnetic transition is supported by VSM measurements performed at room temperature for samples milled for 1, 6, 10, 33, and 52 h. The VSM data confirmed the presence of a ferromagnetic phase at extended milling times, characterized by a progressive increase in coercivity (Hc) and a sharp decrease in saturation magnetization (Ms). X-ray diffraction (XRD) patterns corroborated the phase identification and structural information revealed by Mossbauer spectroscopy.,These findings highlight the capability of MA to induce phase transformations and demonstrate that the combination of MS and VSM is highly effective for tracking the magnetic transition from paramagnetic FeSe2 to ferromagnetic Fe7Se8.