Color refers to the diamond's lack of color. The color grade is actually grading the whiteness of the diamond. The GIA color grading scale starts at D(colorless) and goes to Z(strong tint of yellow). D is the highest possible color grade and Z is the lowest possible grade on the white diamond scale.
Color manifests itself most commonly in a diamond as a pale yellow. This is why a diamond's color grade is based on its lack of color. The less color a diamond has, the higher its color grade. Color is generally considered the second most important characteristic when selecting a diamond. This is because the human eye tends to detect a diamond's sparkle (brilliance and fire) first, and color second.
Although many people consider gem quality diamonds to be colorless, truly colorless diamonds are very rare. Most diamonds used in fine jewelry are nearly colorless exhibiting slight tints of yellow or brown. Color grades are determined by comparing each diamond to a master set of graded diamonds. Diamond color is determined by looking at the side of the diamonds, not the table/top.
Flouresence is the appearance of slight tints of color, usually light blue or purple, when exposed to ultra violet light. Not all diamonds exhibit flouresence and it doesnt play a factor in the color grading or clarity grading of the diamond. We however make sure it is noted on all diamond grading reports as an additional identifying charecteristic of your diamond. Even strong flouresence usually has no or little effect on the appearance of the diamond to the un aided eye. In some circumstances flouresence can actually increase the value and appearance of a diamond. Your Jewelry Box diamond buyers inspect and hand select diamonds that exhibit extraordinary briliance and fire. We will not offer for sale any diamond we believe would be negatively effected by flouresence.