[The Impacts of the Variation of Myanmar Jade Component on Its Infrared Spectroscopy]

Myanmar jade is crystalline aggregate with the major mineral of jadeite. Jadeite can be represented by the crystal-chemical formula NaAlSi2O6. Isomorphous substitution occurs in the natural jadeite frequently, with replacement of Na by Ca, and replacement of Al by Mg, Fe, Cr etcetera, which makes the component of Myanmar jade much more complex and leads to the variation of its physical features, including color, transparency, refractive index, specific gravity and infrared spectrum characteristics, forming different types of Myanmar jade. The studies show that the vibrational spectra characteristics of the Myanmar jade varies depending on the substitution of different elements. In this work, we studied the impacts of the variation of Myanmar jade component on its infrared spectroscopy. 10 Myanmar jade samples which consisted of different chemical composition were measured using Fourier Transform Infrared Spectroscopy (FTIR), and results show that the IR absorption peaks shift to higher wave numbers, as the atomic ratio of Na/Na+Ca of the samples increases. In the low wave number region, the wave number of the IR absorption peaks at 424, 576 and 658 cm(-1) and the atomic ratio of Na/Na+Ca of the samples share fine linear correlation, and the correlation coefficients (R2) are, in order, R1(2)=0.9442, R2(2)=0.9283, R3(2)=0.9097. We can utilize infra-red spectrum technologies combined with linear model built by us in this work to predicate the atomic ratio of Na/Na+Ca of the unknown Myanmar jade samples. As the atomic ratio of Na/Na+Ca of the unknown Myamar jade samples equals 0.8, the IR absorption peaks should be at 658.7, 574.5, 422.5 cm(-1). If the wavenumbers of the IR absorption peaks are less than 658.7, 574.5 and 422.5 cm(-1), the atomic ratio of Na/Na+Ca of the unknown Myanmar jade samples is less than 0.8, which is indicating that the unknown Myanmar jade sample isomphacitic jade, while the wavenumbers of the IR absorption peaks are more than 658.7, 574.5 and 422.5 cm(-1), the atomic ratio of Na/Na+Ca of the unknown Myanmar jade samples is more than 0.8, which is indicating that the unknown Myanmar jade sample is jadeitic jade. The studies of this work offer a super-quick time-saving and labor-saving nondestructivetesting method for using infrared spectrum technologies to test Myanmar jade samples, analyze their component and predicate which mineral styles the unknown samples are.