Optical Spectroscopy

In:  Reviews of Mineralogy and Geochemistry, volume 78

George R. Rossman
Division of Geological and Planetary Sciences
California Institute of Technology
Pasadena, CA 91125-2500, USA


 Optical spectroscopy is concerned with the measurement of the absorption, reflection and emission of light in the near-ultraviolet (~250 nm) through the mid-infrared (~3000 nm) portions of the spectrum.  The human interface to the geological and mineralogical world is primarily visual. Optical spectroscopy is, in particular, well suited to investigating the origin of color in minerals. The reflection spectroscopy of minerals has been motivated to a large extent by interest in remote sensing. Emission spectra are usually studied in reference to luminescence phenomena. Studies of mineral color, metal ion site occupancy, oxi­dation states and concentrations have generally been done with ab­sorption spectroscopy. This chapter concentrates on single crystal absorption spectroscopy.

Forsterite Spectrum

Optical absorption spectrum of forsterite showing absorptipon bands from Fe2+ in both the M1 and M2 sites.