A material is birefringent if the index of refraction differs for incident electromagnetic waves with different polarizations. Examples of birefringent media include calcite (CaCO3), quartz (SiO2), and ice (H2O).
The separation of a beam of light into two beams (ordinary and extraordinary) as it passes through a doubly refracting material or object.
() The magnitude of the difference in the index of refraction of birefringent minerals i.e. that is all minerals that are nonisotropic (All minerals that crystallize in the tetragonal, hexagonal, orthorhombic, monoclinic, and triclinic crystal systems).