Raman Spectroscopy as a Tool for the Quantitative Estimation of Chromium Aluminum Oxide Content in Chromite

Raman spectroscopy has been applied to study a range of chromites (Fe2+, Mg)(Cr, Al, Fe3+)2O4 with variable chromium to aluminum to iron contents to ascertain conclusions about possible correlations between the chromium concentration and the position of the main Raman peaks within this mineral. Our intention was to examine chromite grains from different paragenesis, which vary significantly in their chromium content, to observe changes in the Raman spectra of this mineral. It was found that a negative correlation exists between the chromium number, calculated from the electron microprobe data, and the Raman peak number. Chromite grains with high chromium numbers show a low Raman peak, whereas samples with low chromium number show a higher Raman peak. Therefore, it is possible to infer a relationship between the mineral composition and Raman bands for this type of spinel. The measurements have clearly shown that it is possible to draw precise conclusions about the chromium content of the mineral based on the Raman peak alone. This finding supports a possible application of portable Raman devices on Earth or in space for asteroids and planets.