La microspectrometrie Raman des grenats X₃Y₂Z₃O₁₂: I. La serie calcique naturelle ouvarovite-grossulaire-andradite

The Raman spectra of forty calcic garnets belonging to the two continuous solid-solution series uvarovite-grossular and grossular-andradite are compared and contrasted. An examination of the wavenumber position of the sixteen major bands identified reveals trends which are reasonably linear for the principal high and low frequency bands which are under the indirect control of the trivalent cations. On the other hand for certain medium frequency bands it seems that the ionic radii and/or the atomic masses of the trivalent cations act directly by creating specific bands which can be considered as "chemical markers' of Al³⁺, Fe³⁺ or Cr³⁺. -from Authors