|Thick section of a garnet. The spectrum is shown below.
This piece of crystal has been bought as a tourmaline section
perpendicular to the optic axis thus non pleochroic. In fact, after
Raman examination, the mineral was identified as a garnet (pyrope type).
The high intensity bands in the NIR region are absorptions due to Fe2+
crystal fields transitions. A third band is also normally present at
higher wavelengths beyond the range of the present spectrometer.
forbidden transitions typical of Pyrope - Almandin series can also be
seen in the visible below 700 nm.