Stones with the least amount of color possibly are generally preferred when shopping for a diamond. There are five broad categories of color.
Colorless diamonds are the most rare and valuable of all diamonds. Unlike the D/E color stones which display virtually no color, F colored diamonds, when faced down by a gemologist, display a nearly undetected amount of color.
In the face up position, diamonds in the near colorless range, appear to have no color but do display a slight amount of color when viewed face down against a perfect white background. Once the diamond has been mounted, this trace amount of color will be undetectable to an untrained eye. Such diamonds offer a tremendous value for their price.
When exposed to an ultraviolet light source, some diamonds display a visible light called fluorescence that can be measured as inert, faint, medium or strong. Although diamonds can fluoresce white, yellow, orange and other colors, the most common fluorescence is blue. In standard lighting conditions, fluorescence usually has no effect on a diamond’s appearance. A yellow colored diamond can appear whiter because of a strong blue fluorescence but, in some rare cases, that can also make a stone appear milky or oily. This milky or oily effect applies to a small number of “strong” and “very strong” fluorescent stones and is called an “over blue”.
It is very difficult, if not impossible, for most people to tell the difference between one color grade to another but the price difference can be significant. Diamonds in the D-F range will always be demanded by the purists at heart but the diamonds in the G-I range can still offer you a tremendous value while still achieving a “colorless” look. If you are trying to maximize the size of your stone while shopping on a budget, “J” diamonds are near colorless and the most affordable. Choosing a diamond with medium or strong fluorescence is also something that you may also want to consider. Since the prices of these stones are slightly discounted, they offer the affordability of a higher color stone but without the premium.