FLUORESCENCE CHARACTERISTICS OF BLUE AMBER FROM THE DOMINICAN REPUBLIC, MEXICO, AND MYANMAR.

Amber shows various luminescence phenomena under UV illumination. Amber with very strong blue fluorescence under sunlight or D65 illumination can appear blue to the unaided eye when placed on a black background. Amber showing this effect is highly sought after in the Chinese gem market and referred to as "blue amber." Almost all commercial blue amber is mined from the Dominican Republic, Mexico, and Myanmar. In this study, we collected and characterized the appearance, gemological properties, UV-visible light absorption spectra, and 3D fluorescence spectra of blue amber from these three producing areas. The results show that blue amber from the Dominican Republic generally emits much stronger fluorescence than the other two origins, with narrow triple-peak emissions near 450, 474, and 508 nm. Mexican and Burmese excitation-emission maps present several distinct emission and excitation wavelengths. Additionally, distinctive UV/visible/near-infrared absorptions at 412 and 441 nm appeared only in blue amber from the Dominican Republic. The combination of appearance, UV-Vis-NIR spectroscopy, and excitation-emission mapping may assist in the separation of blue amber from these three localities. [ABSTRACT FROM AUTHOR]