Fluorescence Spectral Characteristic of Blue Amber from Dominican Republic, Mexico and Myanmar

The blue ambers studied here are caused by the fluorescence, not the body colour. The purpose of using the fluorescence spectrophotometer to analyze the fluorescence spectra of blue ambers from Dominican Republic, Mexico and Myanmar is to contrast the fluorescence spectra and luminescence characteristics. Through experiments tests, the authors got spectra, the best excitation light source and the test range. The authors also analyzed the relationship between the shape, the peak position, the intensity and degree of smoothness of fluorescence spectra from different origins of blue ambers. The results are as follows:Strong fluorescence emission of blue ambers mainly occurred in the blue region of the visible spectrum range. The optimal excitation light of Dominican blue amber is 413 nm, with two main peak shapes and a shoulder peak, respectively located near 450, 474 and 507 nm.Two main peaks (450 and 474 nm) show equal height in samples, and the 450 nm peak is lower than the 470 nm in samples with green fluorescence. The optimal excitation light of Mexican blue amber is indeterminate, with a relatively lenient peak consisting of multi peak stacks. The main peak is located at 439 nm, but two peaks will appear in strong fluorescence, which are located at 415 and 435 nm respectively. The optimal excitation light of Myanmar blue amber is 413 nm, with its peak shape and peak position similar to those of Dominican amber. Its peaks are located at 450, 475 and 508 nm, and the 450 nm peak is higher than the 475 nm peak; but when the fluorescence becomes weak, the best excitation source changes to 399 nm and two main peaks change to 433 and 451 nm accordingly. Blue ambers from different localities show different fluorescent colours and intensities under the same light source and the fluorescence spectra are not the same, either. Blue and blue-green fluorescence are mainly produced by the aromatic compounds, and this conclusion is based on previous research results. The authors tentatively assume that they are anthracene, perylene or its derivatives. The reason for the differences in the fluorescence spectra of blue ambers from different origins may be related to the relative content and different varieties of the substances which induced fluorescence.