ANÁLISE DE PEDRAS PRECIOSAS APREENDIDAS PELA POLÍCIA CIVIL DO ESPÍRITO SANTO POR ESPECTROSCOPIA RAMAN PORTÁTIL

ANALYSIS OF SEIZED PRECIOUS STONES BY THE CIVIL POLICE OF ESPÍRITO SANTO BY PORTABLE RAMAN SPECTROSCOPY. The identification of gemstones requires increasingly precise analytical methods due to advances in synthesis and treatment techniques, which heighten the risk of fraud. Portable Raman spectroscopy stands out as a non-destructive and efficient tool for these analyses, providing detailed structural information. This study aimed to apply portable Raman spectroscopy to the characterization of gemstones seized by the Civil Police of Espírito Santo (PCES) and contribute to the creation of a spectral database. Eleven seized samples and seven authentic gemstones from the Federal Institute of Espírito Santo (IFES) were analyzed using a portable Raman spectrometer, along with refractive index and absolute density measurements. The results revealed discrepancies between the presumed classification and the actual composition: the supposed blue emeralds were identified as apatites, while the alleged topazes exhibited spectral characteristics of authentic amethysts. Multivariate statistical analysis (principal component analysis, PCA) and hierarchical analysis demonstrated distinct groupings, aiding in sample differentiation. The study confirms the potential of portable Raman spectroscopy, combined with chemometrics, for gemstone identification, reinforcing forensic investigations and improving gem authentication protocols.