RAMAN-SPECTRA OF VARIOUS TYPES OF TOURMALINE

A large number of different tourmalines are investigated by Raman spec troscopy in the spectral range 150-1550 cm(-1). According to their che mical composition, the studied tourmalines can be classified into thre e main groups: buergerite-schorl, G1; elbaite-type, G2; and dravite-bu ergerite-uvite, G3. It is shown that the same classification of tourma lines can be established on the basis of their Raman spectra. Bands fo r G1 are centred at about 230 and 670 cm(-1), the spectra being charac terized by a single peak at 238+/-2 cm(-1) and three resolved peaks at 635+/-3, 674+/-3 and 697+/-3 cm(-1); G2 has a sharp peak at 224+/-2 a nd two well separated peaks, one at 638+/-3 cm(-1) and the other highe r than 707 cm(-1); G3 is characterized by two peaks at 215+/-3 and 237 +/-3 cm(-1), with a smoothed spectral band centred at about 670 cm(-1) .