Synthesis and characterization of purple NaAlSi2O6 jadeite under high pressure and high temperature

The forming conditions of natural jadeite were simulated with a reasonable synthetic process. According to the molecular composition of purple jadeite, Al2(SiO3)3, Na2SiO3·9H2O and MnO were selected as raw materials which were thoroughly mixed and then quenched at 1100 °C. Finally, the experiments were carried out under the range of 3.5-4.5 GPa and 1200-1500 °C. X-ray diffraction and field emission scanning electron microscopy (FESEM) show that the synthesis of crystalline mineral samples are jadeites with excellent crystallinity and fine-grained texture. The peak positions of infrared spectra and Raman spectra are consistent with those of natural jadeite showing that the synthetic jadeites have the same modes of molecular vibration with natural jadeite. The synthetic jadeite is purple (violet) in color due to MnO absorption indicated by UV-Vis Spectroscopy. The purpose of this experiment is to simulate geological formation conditions of purple jadeite gemstone and to provide favorable synthesis conditions to enable further research on the coloration mechanisms of purple jadeite.