Magnetic circular dichroism (MCD), which has been used for the study of paramagnetic ions in crystals, is now applied to minerals as a technique complementary to optical absorption. Two garnets from the pyrope-almandine series have been studied by both absorption and magnetic circular dichroism and compared. MCD spectra, being unaffected by the ultraviolet absorption edge, unambiguously demonstrate a distinct band centered at 22700 cm-1 (441 nm) with a half-width of 7000 cm-1 at 17 K. This band, which influences the color of garnet, is assigned to Ti3+, but its intensity and position also permit assignment to Ti-Fe charge transfer or Mn3+ transitions.

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