One of the important optical instruments is a glass prism. It is a transparent optical element with flat, polished surfaces that refract light. In other words, prism is made using optical glass demonstrating that white light is made up of the colors of the rainbow. It can also be used to reflect light, or to split light into components with different polarizations. The traditional geometrical shape of a prism is triangular with a triangular base and rectangular sides. The exact angles between the surfaces depend on the application.