Part of the beauty of diamonds is the brilliance they shine back at the person looking at them. This brilliance is the result of light rays that hit the diamond’s facets. Some of the rays that hit a polished diamond penetrate inward, while some – due to the angle at which they strike the diamond – are reflected off the smooth, polished diamond’s surface as white light.
Some of the rays that penetrate the diamond are broken and are reflected back through the square facets of the crown. This reflection creates a sparkle – the diamond’s “fire.” The rays that are reflected through the table as white light are called “brilliance.”
One of the unique qualities that characterizes a polished diamond’s beauty is its ability to break down a ray of light that penetrates the diamond at a certain angle and return it without it passing through. This quality creates a mirror-like effect, which bounces light back to the viewer and keeps him from looking “through” the diamond.
The rays of light that pass through the diamond’s table whole and appear as white light and the rays that are reflected through the facets surrounding the crown are broken down like a prism, and divided into the colors of the spectrum: red, orange, yellow, green, blue, and violet. These colors flash through the facets , and the play of colors at different angles gives the diamond the illusion that it is bursting with fire and brilliance.
Courtesy of Talking Diamonds: A Lexicon of Diamond World Technology by Shalom Lissitzky
