Pleochroism

Pleochroism of cordierite shown by rotating a polarizing filter on the lens of the camera
Pleochroism of tourmaline shown by rotating a polarizing filter on the lens of the camera

Pleochroism is an optical phenomenon in which a substance has different colors when observed at different angles, especially with polarized light.[1]

  1. ^ "Pleochroism in minerals". Webmineral.