Rockbridgeite Visible Spectra (380 - 1100 nm)
The rockbridgeite spectrum is an excellent example of Fe2+ - Fe3+
intervalence charge transfer. The mineral is essentially black in
hand specimen (48K).
In a thin section (104K), the color
changes from dark green to pale yellow depending on the direction of polarization of
the incident light. When the incident light is vibrating along the Fe-Fe direction,
strong absorption occurs and the mineral is dark green.
Image of the rockgridgeite absorption spectrum
- GRR 45 spectrum, 6K;
0.015 mm thick sample from Hagendorf, Germany.
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