Gemmological Characteristic of Imitated Turquoise

By gem microscope, polarizing microscope, scanning electron microscopy(SEM), X-ray powder diffraction spectrometer (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy, the gemmological, mineralogical and spectral characteristics of the imitated turquoise samples were studied, which appeared in Hubei jewelry market. The results showed that the imitated turquoise samples are mainly composed of barite,and relative density is 2.83-3.08. The imitated turquoise samples are cryptocrystalline and have irregular fracture, which can be struck with a knife and not reacted with hydrochloric acid. The appearance of imitated turquoise sample is similar to turquoise, but the composition and the structure are quite different.Combined with SEM, XRD, FTIR and Raman spectroscopy test results, the imitated turquoise samples might be solidified with barite powder and organics. In routine tests, it can be quickly and effectively identified from the natural turquoise by using infrared spectroscopy or Raman spectroscopy.