Manganese Minerals.

 

                                            Raman Main Page

                                                                               Rhodonite section

Thick section of rhodonite( ~ 100µ to 200µ). The whole mineral has a pink color due to Manganese but this color is not deep enough to be seen on such a section.

Raman spectra of Rhodonite with 532 and 633 nm laser. Note that the 633 nm spectrum does not exhibit in that case the bright fluorescence of manganese.
Some green crystals are also present in the Rhodonite section. This mineral is Diopside as seen on the figure below. This spectrum has been recorded only with the 633 nm laser

 

                                                           Spessartine crystal 

Piece of Spessartine from Tanzania and spectra below. The red curve is a spectrum recorded with the laser from THORLABS emitting 3 to 4 different wavelength lines. The mineral can still be identified at a somewhat reduced resolution.

 

                                                                                   Rhodochrosite crystal

Piece of Rhodochrosite from Peru.

No preparation has been made to record the spectrum below at 532 and 633 nm. Spectra are compared to calcite. The CO3 stretching vibrations at about 1095 cm-1 are quite similar for Rhodochrosite and Calcite. Only at very low frequencies can the two carbonates be differentiated.