Choosing the right color for your diamond is based on personal preference. It's important to remember that you are generally searching for a stone with little to no color.
Diamonds are colored when the crystals grow inside the earth. Tiny traces of some elements like nitrogen can color the crystals. In addition, the pressure involved in the diamond formation creates distortion in the crystal structure which is believed to also contribute to its color.
The color evaluation on gem‐quality diamonds is based on the absence of color. The Gemological Institute of America (GIA) uses a 12‐letter alphabetical scale of D to Z. Using this scale, the diamond on the lower end of the scale (D) will have the least amount of color – it is considered a colorless stone. The diamond at the higher end of the scale (Z) has deeper tones. However, when a diamond's color is more intense than the "Z" grading, it enters the realm of a "Fancy Color" diamond. In this case, the intensity of the color in the diamond can play a significant role in its value. The value of a Fancy Colored Diamond can surpass that of colorless diamonds if the intensity of the color is high and the color is rare.
How the diamond is set can make a difference in color too. Color is more important in rings than earrings and pendants because the diamond is usually larger.
Keep in mind that color is only one of the 5Cs so even when a stone has a visible tint, it can still be very lovely when mixed with good clarity and cut.