How Size Effects Your Cost
The larger the diamond, the more rare. As you increase the size (carat weight), you will find that the cost is exponentially impacted. Diamonds are bought and sold based on the 'price per carat' for that diamond's color, clarity, and carat weight. As the size increases, the price per carat also increases. The end result is a dramatic, exponential increase in cost. For example, a 1/2 carat diamond may cost $1,100, but the same quality diamond at 1.0 carat will cost $5,000. The size is doubled, but the cost is 4.5 times as much.
And don't forget Cut! A better quality Cut will also cost you more.