Ordinary rays and extra ordinary rays?

Answer 1

In case of some crystals such as calcite, when light is passed through two rays come out giving rise to two images. One is found to be stationary and the other one is moving around the first as we rotate the crystal about the line of incidence.

The stationary image is known as ordinary image and the moving image is extraordinary image. The stationary image is due to ordinary ray and extra ordinarily moving image is due to extra ordinary ray.

Ordinary ray obeys all the laws of refraction where as the extra ordinary does not do so.

This is because the light entered into the crystal has been polarized.

Answer 2

In mineralogy, ordinary rays are light waves that travel at a consistent speed through a crystal, while extraordinary rays are waves that split into two different speeds when passing through a crystal. This phenomenon, known as birefringence, is characteristic of anisotropic minerals that have different optical properties in different crystallographic directions. By analyzing the behavior of ordinary and extraordinary rays, mineralogists can identify and study the unique crystal structures of minerals.