The absorption spectra of pieces of a high-iron, high-calcium rhodonite crystal have been measured for incident polarized radiation with the electric vector parallel to the principal axes of the refractive index indicatrix, in the range 4500 to 31000 cm-1 at 18 K and from 2000 to 30000 cm-3 at room temperature. Absorption spectra of crystals of the same rhodonite and of a low-iron, low-calcium rhodonite were taken over the same ranges, with the electric vector of the incident light parallel to the axes of the indicatrix section parallel to (100). The change in the axis directions with wavelength between 16000 and 31000 cm-1 for the (100) slice of low-iron rhodonite is described; the change for the high-iron rhodonite principal axes between 2000 and 31000 cm-1 was within the limits of error. Powder spectra of the two rhodonites and of a low-iron, high-calcium rhodonite were taken between 300 and 2000 cm-1. Band wave-numbers at 18 K and room temperature plus the intensities and polarization ratios for the high-iron rhodonite at 18 K have been tabulated. Comparisons among the powder spectra permit the vibrational bands to be assigned to various groups of sites. Comparing the high- and low-iron rhodonite crystal spectra permits most non-vibrational bands to be assigned to Fe2+ or Mn2+dd transitions. The approximate symmetry of the preferred Fe2+ site M(4) was used as a basis for classification of the Fe2+ bands.

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