Editing Birefringence (section)

===Other cases of birefringence===

[[File:Rutile birefringence.gif|right|thumb|Birefringent [[rutile]] observed in different polarizations using a rotating polarizer (or ''analyzer'')]]
Birefringence is observed in anisotropic [[elastic deformation|elastic]] materials. In these materials, the two polarizations split according to their effective refractive indices, which are also sensitive to stress.

The study of birefringence in [[shear wave]]s traveling through the solid Earth (the Earth's liquid core does not support shear waves) is widely used in [[seismology]]. {{citation needed|date=July 2020}}

Birefringence is widely used in mineralogy to identify rocks, minerals, and gemstones.{{citation needed|date=July 2020}}
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