What is "pleochroism"

Pleochroism \Ple*och"ro*ism\, n. [Gr.? mor? + ? color.] (Crystallog.) The property possessed by some crystals, of showing different colors when viewed in the direction of different axes.

n. (context physics English) The optical phenomenon in some colored, transparent crystals (such as tourmaline) in which the color is different in different directions.

n. the phenomenon of different colors appearing when certain crystals are viewed from different directions

Pleochroism is an optical phenomenon in which a substance appears to be different colors when observed at different angles, especially with polarized light.