Characterization of Indian serpentine by X-ray diffraction, photoacoustic spectroscopy and electron paramagnetic resonance spectroscopy

► PAS and EPR studies showed the presence of Mn2+ and Fe3+ ions in serpentines. ► Mn2+ occupied octahedral Mg2+ sites. ► Fe3+ occupied mainly tetrahedral Si sites and a few octahedral Mg2+ sites. ► A broad EPR signal observed in some samples were attributed to presence of Fe clusters or MgFe2O4.