Many experts name color as the number one consideration in choosing a diamond. A diamond’s color is graded on an alphabetical scale from D-Z, with D being absolutely colorless and Z being light yellow. Beyond “Z”, a diamond is considered to be an exotic or “Fancy” color.
Since color differences can be so subtle, they are impossible to determine by the untrained eye. To grade a diamond, gemologists often place it on a white background next to another diamond that has been previously graded.
If all other factors are equal, the less color in a diamond or the higher color rating, the more valuable a diamond becomes. Likewise, as the amount of color increases, the price of a diamond decreases (though this does not necessarily reduce the beauty of a diamond.)