Pleochroism

noun

1. The property possessed by some crystals of exhibiting different colors, especially three different colors, when viewed along different axes.
2. In crystallography, the variation in color observed in some crystals when viewed in different directions, due to the fact that the rays having vibrations in different planes suffer absorption in different degrees.
3. The property possessed by some crystals, of showing different colors when viewed in the direction of different axes.
4. The optical phenomenon in some colored, transparent crystals (such as tourmaline) in which the color is different in different directions.
5. the phenomenon of different colors appearing when certain crystals are viewed from different directions