Determination of titanium content in pyrope by Raman spectroscopy

The titanium content of pyrope garnet can be quantified using the intensity of a Raman band at about 830 cm^-1 that is normalized to the 363 cm^-1 band using a spectrometer-specific calibration using 10 to 15 chromian pyropes from Bohemia, Czech Republic. An accuracy of 0.025 wt% could be achieved for TiO₂ contents between 0.17 and 0.67 wt% TiO₂ with a Raman spectrometer with a spectral resolution of better than 3.9 cm^-1. The technique can be used in petrological and gemmological studies.