A Diamond of color G and SI1 Clarity grade will have a certain category of pricing when its range lies between 0.50 - 0.69 carats. When you take that same quality Diamond and increase its size to the next price category, which is the 0.70 - 0.89 carat range, the price increase will be approximately $1,100 per carat . If we further increase to the 0.90 - 0.99 carat range, the price increase will be approximately another $800 per carat . A further increase to 1.00 - 1.49 carat range, and the increase will be approximately another $800 per carat . A final increase to the 1.50 - 1.99 carat range, will increase the price per carat to $1200.

Color:

Supposing you have selected a 1.00 carat Diamond of K color and VS1 Clarity. If you move up to an H color, you will pay approximately an extra $1,700 per carat . By moving up to F color, the increase will be approximately $1,100 per carat . Again an improvement to D color will result in another increase of $900 per carat.

Clarity:

Starting with a 1.00 carat Diamond of G color and SI1 Clarity, if you move up to a VS1 grade you will pay approximately an extra $1000 per carat . Move up to VVS1, the increase will be approximately $700 per carat . Improve the clarity to IF and the increase will be approximately $700 per carat .

Cut:

Cut is a bit more complicated and depends on various factors, like the quality of Diamond being considered. Ideal cuts are generally much more expensive than the others. It all comes down on the quality of the cut, but lots of ceases have to be studied before making a final decision.

Finally we can see that a diamond's per carat price goes up when we go for higher clarity or better color grades. The price is also affected by the choice of carat range.