Glaucophane Prasinite from Viu Italy.

Study by Raman microscopy of a rock section coming from the village of Viu in the Alps of northern Italy. Three types of samples have been examined: a thick section (100 to 200 µ thickness), a normal thin section and a polished slab. Images of the 3 preparations will be used to identify the locations of the Raman spectra at 532 and 633 nm. About 13 different minerals  have been discovered in this rock with the Raman microscope.

Glaucophane

Spot 1: pleochroic crystal of glaucophane, colorless to blue.

Plane polarized reflection image. Spot 2 is an opaque mineral: magnetite. See spectra on page 5.

Raman spectrum of the glaucophane crystal of spot 1 showing a strong spectrum variation according to direction of polarization of the laser light.

Phlogopite + Quartz

The spot 3 on the first image above seems to be a mixture of a colorless and a green mineral. The Raman spectra can be interpreted as the superposition of 2 minerals: Phlogopite and Quartz. Another place of this section (20 below) gives a similar spectrum. The pure phlogopite spectrum can also be found (spot 8).

Rutile

The small crystal number 3 on the first figure is Rutile as shown by the spectrum above. It can be seen with both lasers.