Some of these categories affect beauty a great deal, others very little or not at all, but all categories affect price. Even slight nuances can change price dramatically. All legitimate diamond grading uses the GIA scale, worldwide. The Four C's Carat Weight Carat is a unit of weight equal to one-fifth of a gram. As the carat size increases, so does the price.
Some abrupt increases happen when going from size to size.
Price jumps when you cross size thresholds. Have the jeweler itemize the weight of the center diamond and the combined weight of the side diamonds separately. The price ranges given vary depending upon the actual grade of the diamond. Here is an example of a round cut diamond. Marquises cost about 20 percent more than rounds.