Buying a diamond is the ultimate shopping trip; a little education will make it all the more enjoyable. The universally accepted criteria used in diamond evaluation are known as the 4C's:
Carat Weight ,
Color is personal: some people like a diamond with an ice-cold whiteness (colorless or near-colorless), while others prefer the golden glow of a warmer color. Diamonds with no color like D, E, F, are very rare and are more expensive than near-colorless (G, H, I, J) diamonds.
Diamonds with a faint tinge of color (K, L, M, N, O) have a slightly warm color and are more affordable. For those who want a larger diamond within a certain budget, selecting diamonds with a lower color grade may be the best option.
Less color is generally preferred but "fancy" is rare. Did you know that diamonds come in every color of the rainbow? EGL USA has handled thousands of these rare "fancy colors" and carat for carat, they're the most expensive objects on the entire earth. Some of the highest prices paid per carat are for colored diamonds.
Fancy colors include brilliant yellows, steely blues, soft pinks, fiery oranges and more; there's even fancy white and black. If the color is natural, as opposed to treated, the prices of these fancies can be extremely high.
Below is the official color grading scale recognized by the international diamond trade and laboratories like EGL USA. The scale runs in order of rarity from colorless on the left to light yellow on the right.