[Study on the vibrational spectra characters of Taiwan blue chalcedony]

Blue chalcedony is one of the precious gems produced in Taiwan, known as "Taiwan Sapphire" in the world. The infrared absorption spectrum and Raman spectrum were employed to study the characters of the vibrational spectrum of the blue chalcedony with different color and texture. It was indicated that the Taiwan blue chalcedony shows the typical spectral characteristics of the vibrational spectra of the quartziferous jade. The infrared absorption spectra show that the strongest absorption region 1 250-1 110 cm(-1) is induced by Si-O asymmetric stretching vibration, the medium-intensity absorption band 800-600 cm(-1) is mainly induced by the Si-O-Si symmetric stretching vibration and the Si--O bending vibration displays the peaks in the range of 600-300 cm(-1). The Raman spectra scattering peaks of the Taiwan blue chalcedony samples are mainly at 499 cm(-1) +/-, 464 cm(-1) +/-, and 208-214 cm(-1) and are mainly induced by the Si-O symmetric bending vibration, Si-O bending vibration, and [SiO4] rotational vibration or translation vibration of the "Moganite" quartz.