Abstract: By using the infrared reflection spectrum analysis technique,the filled,pressed,imitated and natural turquoises on gem markets are investigated.The results show that the IR peaks at 2 934~2 924,2 863~2 854 cm^-1 are resulted from the asymmetrical stretching vibration and the symmetrical stretching vibration of CH₂and the strectching vibration of ν(C＝O) peaks lie at 1 739~1 718 cm^-1 in polymer of the treated and imitated turquoises.The imitated truquoises have the characteristic spectra of the asymmetrical stretching vibration and the symmetrical stretching vibration of CH₂,and the vibration of ν(C＝O) and characteristic absorption bands of themselves.But,they lack any typical peaks of stretching vibration of hydroxyl of natural turquoise(3 507,3 465 cm^-1).These typical IR spectra play an important role in distinguishing the treated and imitated turquoises from the natural turquoise.