The Ray of Light [SEP] material used
The Ray of Light
The Ray of Light, also known as Le Coup de Soleil, (c. 1665) is an oil on canvas painting by the Dutch painter Jacob van Ruisdael.
It is an example of Dutch Golden Age painting and is now in the collection of the Louvre Museum.
This painting was documented by Hofstede de Groot in 1911, who wrote; "664. THE BURST OF SUNSHINE (" Le Coup de Soleil "). 
Sm. 11. A road leads diagonally across the picture from
be carefully adjusted to maximize the optical performance. The angles used will vary based on the refractive index of the gem material. When light passes through a gemstone and strikes a polished facet, the minimum angle possible for the facet to reflect the light back into the gemstone is called the "critical angle". If the ray of light strikes a surface lower than this angle, it will leave the gem material instead of reflecting through the gem as brilliance. These lost light rays are sometimes referred to as "light leakage"