Color refers to the amount of tint in a diamond that happens naturally while it was being formed. Tint is caused by the presence of other elements that give it different colors. The most common element present in a diamond is nitrogen and this causes a diamond to be yellow. The less amount of nitrogen the whiter the stone.
The normal color scale are D to Z and classified into five; colorless, near-colorless, faint yellow, very light yellow, and light yellow. Diamonds past this color scale and diamonds with other colored tints are called "fancy colored".