1. On a clear day there may be abnormal refraction of light causing distortion in the appearance of features.

2. Once again, facets are cut, but two more than on the top, for more effective refraction of light.

3. The colour is due to the refraction of light off the rock flour deposited in the lake on a continual basis.

4. Birefringence definition is - the refraction of light in an anisotropic material (such as calcite) in two slightly different directions to form two rays —called also double refraction

5. Birefringence is formally defined as the double refraction of light in a transparent, molecularly ordered material, which is a manifestation of the existence of orientation-dependent differences in refractive index.