Caracterização da Esmeralda de Pirenópolis (Goiás, Brasil Central) por Espectroscopia no Infravermelho (Ftir)
Palavras-chave:esmeralda, espectroscopia no infravermelho, berilo, gema, Pirenópolis.
The infrared spectra of two natural samples of powdered emerald from Pirenópolis (Goiás State, Central Brazil) were measured at room temperature (~ 20ºC). Water molecules occur in two different configurations. Three absorption peaks (3656, 3592 and 1624 cm-1) record the vibrations of the type-II H2O. The peak absorption at 3691 cm-1 is assigned to type- I H2O vibrations. In addition, CO2 (2358 cm-1) and CH4 (2927-2925 cm-1) molecules were also detected in the FTIR spectra. These data can be applied to distinguish the Pirenópolis gem from the other Brazilian emeralds as well as its synthetic equivalents.