The GIA has studied and documented the relationship between light and a polished diamond for many years. Research has allowed them to understand how different facet sizes, arrangements, and angles could either improve or reduce a diamond’s appearance. This understanding led to the development of the GIA Diamond Cut grading system.
When diamonds and light interact the results are amazing. The relationship between diamonds and light lies in how much light hits the surface of the diamond, enters the diamond, and how the light reflects back from the diamond. The proportions of a polished diamond (its angles and measurements) and the relationship between them have an extraordinary effect on how light performs when it strikes the diamond.
A diamond has three visual characteristics: brightness, fire, and scintillation. Brightness (aka brilliance) is the amount of white light returned from the diamond to the observer, fire is the display of spectral colors created when the white light strikes the diamond’s facets, and scintillation is the flashes of light and contrasting dark areas seen when a diamond, the light source, or the observer moves.
A well-cut diamond will get the most out of its interaction with light. Well-cut diamonds are brighter and more attractive than poorly cut diamonds even if weight, color, and clarity are the same.
To learn more about diamond proportions visit our diamond education section.
