Unheated Pink Sapphire from Madagascar with OH-related 3232 and 3185 cm^–1 FTIR Bands

A new article in the Journal of Gemmology by SSEF gemmologists examines OH-related FTIR bands at 3232 and 3185 cm⁻¹ — peaks that are often interpreted as indicators of heat treatment.

By combining detailed FTIR analysis with Raman identification of inclusions such as goethite, the study shows that these peaks may also occur in unheated stones, underlining why heat determination can be complex. Rather than offering a single definitive answer, this research adds important additional clues and helps refine the criteria used when assessing pink sapphires.