The 4 C's and Comparison Shopping
The GIA color rating ranges from D (total absence of color) to Z (quite yellow, with a brown cast). Color is judged through the side, under suitable light, next to test stones that have been graded for color in a laboratory. We recommend color grades of J or above for fine jewelry such as an engagement ring. However, colors K-M make the larger stone sizes more affordable for those who are not willing to pay the stiff price difference for higher colors. Here's a closer look at the color ranges.
D-F are classified as colorless and are considered investment grades by many; they are much more expensive than the next range of color grades. We call these three "colors for the perfectionist." These people want to know their stones are white as ice, even though when they are mounted it is very difficult, if not impossible, to tell the difference between these stones and those in the near colorless range (G-J), which is found in most commercial jewelry.
The contrast to yellow gold makes borderline stones look white. All diamonds in color categories D through M will face up (appear from the top) white when mounted in yellow gold. Those in colors K-M will face up white when mounted in yellow gold, but will show tinges of yellow when they are viewed from the side or on an angle, or when mounted in white gold. The yellow will be easy to see in colors N-Z.
The cost impact of a difference of one color grade is about equal to a difference of one clarity grade. If your preferred mounting is yellow gold, you may be willing to sacrifice one color grade in favor of a higher clarity grade. Some may actually prefer yellow, as a "warmer" color diamond. But if you feel you have to apologize for the color, you'd be better off with a higher color grade. Bottom line, there is no right or wrong color ~ just personal preference and price tradeoffs.
After dropping through Z, prices begin to rise again based on the intensity of the yellow; very yellow specimens are called "canaries". Canaries and other diamonds of exceptional color (red, blue, green, pink, amber, champagne), are known as "Fancies."
Color seems to be a catchall for many commercial jewelers when they describe stones with yellow in them. Although graded K, the actual grade is often lower. Dishonest jewelers do so because below K the price drops like a stone. In a 1 CT diamond, there's a $1300 price difference between colors K & M at wholesale.
To overstate the color grade is an easy way to cheat the unsuspecting consumer As mentioned above, the color of the mounting can throw off the color grade, to which the best defense is viewing the stone while it's loose. Another factor that would lead a dishonest jeweler to choose color as the grading factor to tamper with, is that it's the most subjective of the 4 C's, within limits. A difference of one grade can be an honest matter of opinion, even between two expert diamond graders. However, if you discover your jeweler has overgraded the color of your diamond by two or more grades, you should request a cost adjustment.