Spectroscopic Studies of Baltic Amber-Critical Analysis

Area of Science:

• Geochemistry
• Materials Science
• Spectroscopy

Background:

• Baltic amber exhibits diverse spectral properties influenced by natural aging.
• Distinguishing natural amber from thermally modified amber is crucial for authenticity assessment.

Purpose of the Study:

• To analyze the effectiveness of various optical spectroscopy methods in differentiating natural Baltic amber from thermally modified samples.
• To investigate spectral changes in amber subjected to controlled thermal modification.

Main Methods:

• UV-VIS absorption spectroscopy
• Fourier-transform infrared (FTIR) spectroscopy
• Raman spectroscopy
• Fluorescence spectroscopy
• Analysis of 25 Baltic amber samples

Main Results:

• Natural amber samples displayed significant variations in UV-VIS transmission edge, IR absorbance ratios (C-H/C=O), fluorescence intensity, and Raman band ratios (C=C/C-H).
• Thermal modification above 150°C caused drastic spectral changes: color darkening, UV-VIS edge shift, increased C=O absorbance, decreased C=C absorbance, and loss of fluorescence.
• Spectroscopic methods reliably distinguished thermally modified amber only when significant spectral alterations occurred (150-200°C).

Conclusions:

• Optical spectroscopy can differentiate thermally modified amber from natural amber, particularly at higher modification temperatures.
• Fluorescence spectroscopy shows potential for distinguishing amber from different geographical origins.
• The natural spectral variability within Baltic amber can sometimes exceed spectral differences caused by moderate thermal modification.