Diamonds are found in nature in a wide range of colors, from completely colorless (the most desirable trait) to slightly yellow, to brown, and then to fancy colors, such as blues, greens, bright yellows, pinks, and even reds. Most diamonds selected for wedding bands are white (clear) or nearly white. A diamond's color is permanent, never changing over time. To be accurately graded for color, diamonds need to be loose or unmounted.
Acting as a prism, a diamond divides light into the colors of the spectrum and reflects this light as colorful flashes called fire. Like light passing through a clear glass window, a colorless diamond allows more light to pass through it than a colored diamond. Because colorless diamonds give off more sparkle and fire, whiter diamonds have a greater value.
To grade "whiteness", or how clear a diamond is, GIA's color scale begins with the highest rating of D (colorless), and ends with Z (concentrated yellows or browns). The color difference between individual steps such as from an F to a G, or from a G to an H, is very slight, yet a single change in color grade can significantly affect a diamond's value. As the chart shows, D, E, and F are considered Colorless, G, H, I, and J are Near Colorless, and all of these top seven grades appear colorless when the diamond is mounted.
Although most people buy the whitest diamond they can afford, many people actually prefer the warmer glow of lower-color diamonds such as grades K through N. While a very faint hint of yellow may be apparent in these diamonds, the color can often be minimized by carefully selecting the right jewelry in which to mount them.
Fluorescence is an effect that causes some diamonds to glow in the dark when exposed to black light. Florescence is not detectable to the naked eye in daylight or under most other lighting conditions and is just another unique identifying characteristic.
Our Take: D, E, and F colors are fabulous, but are frequently out of the price range for many people. Don't hesitate to choose a diamond in the Near Colorless range (G, H, I, and J), if doing so allows you to buy a larger stone or spend less. Most jewelry professionals and consumers realize the excellent value of these diamonds because they face up colorless when mounted.