Diamonds come in many colors, but the typical scale ranges from colorless to yellow. Nitrogen inside the stone causes it to take on a yellow tint, which in turn decreases the amount of light it lets through. So the Less color a stone has the more brilliant it is and the brighter it shines. Because of this correlation colorless stones are considered most valuable and the value decreases with increasing color. The exceptions to this rule are Fancy diamonds, which can bear a deep yellow color that makes them rare and expensive.

The grading scale used to rate diamond color is alphabetical and ranges from D to Z. D represents a purely colorless diamond where as Z is the deep yellow of the Fancy stones.

The difference between two consecutive color grades is so subtle that gemologists use a machine to accurately measure the grades.  The average person usually requires a difference of at least two color grades to see a difference. 

Fluorescence

Fluorescence is the ability of the diamond to glow in ultraviolet light.  It is graded from None to Very Strong and can change the appearance of a diamond's color. Faint fluorescence has little to no effect on a stone. Medium and strong fluorescence can actually make a low color grade stone appear whiter, but can make a colorless stone appear hazy or oily.

Diamonds in the D to H color range with faint fluorescence can actually be a sensible purchase since the fluorescence will have little or no impact on the appearance of the diamonds but will lower the price. 

For diamonds with color grade of I or lower, look for faint or medium fluorescence since it will make them look whiter.  

Top Rate Diamonds Color Recommendation: We recommend G color because the diamond still  looks colorless and allows you to realize significant savings compared to the colorless collection (D,E,F). 

For diamonds greater than 1 carat we recommend staying at or above 'I' color because color tint becomes more noticeable in larger diamonds and diminishes the purity of the diamond.