Infrared Spectral Proof of An Out-of-phase Material on Surface Cavity of Almandine

The luster difference on surface cavity of almandine is one of the important proofs for whether the almandine is filled by artificial materials or not.However, it is necessary to identify whether the luster difference origins from the surface-reaching natural mineral inclusions or not.The gemmological characteristics of almandine samples and surface material being weak luster with infrared spectral characteristics are studied by using the conventional gemmological methods and infrared spectrometer, which could determine whether the almandine samples have been filled or not.The results show that the microscope reflectance infrared spectra of the out-of-phase material have apparent absorption peaks at 1 200 to 900, 798, 779 cm^-1, which verify the existence of the natural quartz inclusion instead of artificial fillings.The surface-reaching material being weak luster is not the diagnostic evidence for whether the almandine has been filled or not, while the existence of mineral inclusion may lead to the different luster on the surface of almandine.