Characterization of chrysotile, antigorite and lizardite by FT-Raman spectroscopy

We analyzed samples of antigorite, lizardite and fibrous chrysotile, three representative minerals of the serpentine group, to determine their chemical and structural properties, and their FT-Raman spectra. The low-frequency region of the spectrum (1200-200 cm(-1)). which corresponds to the lattice-vibration modes, was then analyzed, and the observed bands attributed, on the basis of our results. Raman spectroscopy thus proves useful in identifying the three mineral species, despite their strong similarities in structure and chemical composition. The symmetric stretching modes of the Si-O-b-Si linkages vibrate at different frequencies in chrysotile and antigorite. whereas chrysotile and lizardite can easily be identified by analyzing the vibrations of the OH-Mg-OH groups and the bands in the range 550-500 cm(-1).