Tourmaline Mica Schist

Section in polarized light, uncrossed nicols. Assemblage of k-feldspar and quartz, (both clear, low-relief), minor muscovite and biotite, and tourmaline crystals. The tourmaline exhibits pleochrosim as evidenced by the different amount of absorbtion of light in grains oriented either east/west or north/south, the n/s direction being a darker brown.

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