Discriminating real and fake amber using non-invasive LIBS and complementary FTIR analysis

Abstract Amber is one of the most important national treasures in Lithuania, as well as in some other Baltic countries. In the recent era, some other materials that resemble amber have been introduced in the market, which are sometimes sold as real amber. This is considered as fraud and will, in turn, destroy the whole Amber trade. Laser-Induced Breakdown spectroscopy (LIBS) is a developed elemental spectroscopic technique that has been used for qualitative and quantitative analysis for many analytical applications, including the analysis of jewelry, gems and diamonds. In this work, we use LIBS as a quasi-non-destructive elemental analytical technique to differentiate between real and fake amber, as well as differentiate between the different types of real amber. A group of real and fake amber with different colors is used in this study. FTIR was first used as an approved molecular spectroscopic technique for distinguishing between the different samples. After collecting the LIBS data, the LIBS spectra were then compared qualitatively and then evaluated statistically using principal component analysis (PCA). Crater morphology was also compared across samples. The effect of ambient gas was also studied by performing the experiment in both air and argon environments.