Are all pleochroic minerals mafic?

Question

Is pleochroism exhibited only by mafic minerals, or do some felsic minerals also do this?

Answer 1

Not at all.

Pleochroism is defined as "an optical phenomenon in which grains of a rock appear to be different colors when observed at different angles under a petrographic microscope." (wiki)

Polarized light is bent at different angles in the crystal to produce a variety of colors depending on the angle of the crystal, which can vary widely in the rock. A mineral/rock does not have to be mafic to do this to my knowledge. Muscovite is pleiochroic, and it is most definitely a felsic mineral.