Abstract

Raman spectroscopy was used to characterize a synthetic, defect-poor berlinite [𝛼-AlPO₄] single crystal and compare its spectral features with published data and natural reference samples. Measurements were performed with a 532nm laser over 0-4000cm^-1 using calibrated silicon and diamond standards, with spectra collected from rhombohedral and prismatic crystal planes. The principal diagnostic Raman bands occurred near 220, 461, and 1110-1112cm^-1, while the strongest bands were observed at approximately 462 and 1112cm^-1. Their positions were consistent with handbook data obtained using 514nm excitation and with measurements from berlinite samples from Sweden and Germany. Comparison of the examined orientations indicates that the principal band positions are relatively stable, although the available data does not establish complete orientation independence. Further measurements involving additional crystals, controlled polarization, and quantitative intensity analysis are required to define orientation effects more rigorously.

Keywords: Berlinite; 𝛼-AlPO₄; Raman spectroscopy; Diagnostic raman bands; Crystal orientation; Synthetic single crystal; Mineral characterization