When most industry experts discuss a diamond's colour, they are typically referring to a diamond's transparancy, or lack of colour. Diamonds composed of 100% pure carbon without any impurities render completely colorless diamonds. However, almost all diamonds contain some degree of colour impurity caused by lingering traces of nitrogen, boron, hydrogen or other elements. Most diamonds are affected solely by nitrogen traces, which create pale yellowish or brownish tints.
When shopping for a diamond, be aware that the most valuable diamonds have the least amount of colour, no diamond colour. However, it is important to note that there is a class of diamonds known as fancy diamonds which are actual coloured diamonds, including blue diamonds, pink diamonds and even yellow diamonds, if in fact you are looking for coloured diamonds.
When grading a diamond's colour, the stone is examined face-down under carefully controlled light. The diamond's colour is then compared to a "master stone" which has a predetermined diamond colour.
The Gemological Institute of America's (GIA) colour grading system is the diamond industry's standard for diamond colour grading. The GIA's colour grading system begins with D, being the whitest, and continues through the alphabet to Z, for stones that are yellowish or brownish. Before the GIA developed their universal diamond colour grading standard several other diamond colour scales were being used by the international diamond community. The GIA's intention was to completely differentiate their new system from the others. As such, they chose letters D-Z, letters that had never been used for diamond grading before.
D 100% Colorless. The highest colour grade a diamond can receive. D graded diamonds are extremely rare and very highly priced.
E,F Colorless. Exceptionally transparent. Extremely difficult to detect the traces of colour in an E or F graded diamond. These diamonds are rare and highly priced.
G,H Nearly Colorless. Unless these diamonds are compared next to a master stone of higher colour grade, colour is nearly indiscernable. Appear completely colorless when face up. These diamonds are still rare, but slightly less expensive and are considered a good value.
I,J Nearly Colorless. Colour in these diamonds is slightly detectable. The slight amount of colour is imperceptible by the unaided eye once the diamond has been mounted. Superior value.
K-M Faint Yellow. Noticeable colour, although some diamonds in this range can still be fiery and beautiful.
N-Z Very Light or Light Yellow. Noticeable colour. These diamonds are not fit to be sold as gemstones.
Zoara suggests that you do some window shopping for certified diamonds, take a look at diamonds of all colour grades and compare and contrast. The difference in appearance between colorless diamonds and near colorless diamonds may not be detectable, but the price difference can be quite considerable. If you find that you are sensitive to low colour grades, then we suggest you choose a diamond with the colour grade that satisfies you. However, if you have difficulty differentiating between different colour grades, then you may want to consider a nearly colorless diamond.
For those that don't have time to do window shopping, remember that if you are looking to purchase a round brilliant diamond, you have a bit more flexibility in your colour grade. The brilliance of the cut makes it more difficult to detect colour. We recommend selecting a round diamond graded I or higher in colour. It is easier to detect colour in fancy shaped diamonds and for this reason we suggest selecting a fancy shaped diamond graded H or higher in colour.
Many diamonds, when placed under UV light, emit a light glow in the same way that a white T-shirt does. Because there are a small amount of UV rays in regular daylight, some diamonds also exhibit fluorescence in natural light. On more recent GIA Diamond Grading Reports, the fluorescence of a diamond appears as a graded characteristic. Fluorescence can be graded as Inert, Faint, Medium, or Strong. To this day there is still no consensus among industry experts regarding the general impact of fluorescence on a diamond. This is because strong fluorescence in a diamond with a high colour grade (D-H) can cause the diamond to appear milky or cloudy, while strong fluorescence in a diamond with a low colour grade can make the diamond appear whiter. Most of the time, fluorescence has no impact on a diamond's appearance under regular lighting conditions.