Correlations between the infrared spectrum and the composition of garnets in the pyrope-almandine-spessartine series

The i.r. spectrum of 13 analyzed garnets of the pyralspite group has been investigated in the 1400-200 cm-1 region, and correlations have been found between the spectrum and the chemical composition. The results include: typical features in the spectrum of the end-members pyrope, almandine and spessartine; relationships between the spectrum and the pyrope percentage in pyrope-almandine solid solutions; and the influence of the CaO (grossularite) amount on the shape of the low-frequency absorption bands. These data allow a semiquantitative determination of the pyrope percentage in pyrope-almandine solid solutions. © 1973 Springer-Verlag.