If you've ever seen the diamond color scale below, you're probably wondering why it's important. How it applies to shopping for a diamond. How it translates to the cost.
First, the nitty-gritty. The whiter the diamond, the more desired a stone typically is. Since what you're really looking for in a diamond is reflectivity, it's best achieved by a whiter diamond.
Diamond color is classified on a alphabet scale ranging from D-Z with a D colored stone being a vibrant white or colorless to Z having a strong yellow tint.
If you're looking at a diamond, a good way to easily see the color of a diamond is to place the stone facing down on a white piece of paper. The contrast of the paper will make any yellow in the stone pop out. You'll also get bonus points for looking like you're in the know.
When you face the diamond upright, the yellow color isn't quite as prominent because of how the facets reflect light in the stone.
So, how does this translate to buying a diamond? First, determine what you're looking for. For example, if you're looking to have a platinum or white gold setting, you want to aim for a diamond that skews towards the colorless or near colorless range; as the white metal could bring out the yellow undertones of your diamond (similar to the paper test).
The best bang for your buck will be in the near colorless range since these stones are more common. In terms of pricing, you could find a J stone for nearly half the price of a D stone. Each increase in color will translate to an increase in cost of about 15% in the near colorless range. This also will depend on where you go to purchase your diamond.
If you're planning to set your diamond in yellow gold, then you could definitely get away with the faint yellow K-M grade diamonds. The yellow metal will take away hints of yellow in your diamond to the naked eye & could add some nice warmth to the ring overall.
One thing I tell my clients is to consider all the C's together. They are all very important pieces to the diamond buying puzzle. You don't want a D colored diamond with a heavily included stone because all the inclusions will be way more visible.
So, there you have it.
Now, go and get it.