Diamond colors are categorized on an industry scale from D - X for white and yellow diamonds. D is the whitest possible color, while around S diamonds become known as "Fancy yellow Diamonds". You'll also find a variety of other possible colors for diamonds, including blue, pink, green and even brown, though brown diamonds are usually irradiated.
There is no wrong choice when it comes to diamond color. Some people prefer a colorless or near-colorless diamond with an ice-cold whiteness, while others prefer the golden glow of yellow or of another warmer color.
As far as typical costs go, you can expect diamonds with no color (like D, E, F) to be more expensive due to their rarity. Grades (G, H, I, J) diamonds are near colorless and are less expensive.
Seen below is an official color grading scale that will help you to better understand diamond color. This chart is recognized by the international diamond trade and laboratories.