Traditionally there are five shape variations . A diamond's price is directly related to the combination of the four C's. A diamond of twice the weight of another is much rarer and therefore more precious and will have a higher price per carat. Weight also has psychological as well as scarcity value since a diamond of 1 carat or slightly higher is worth considerably more, weight for weight, than a diamond of 0.90 carat because it has reached or exceeded the conventional unit of the complete or full 1.00 carat. The same principle applies at the dividing line for 2 and 3 carat diamonds etc.-as the price increases in leaps with each complete and full carat unit.
Color also plays an important role in determining a diamonds value.
The price of a diamond varies quite sharply with color. Moves in clarity grades will affect the price in a similar manner. However, due to the numerous different possible combinations of Clarity, Color and Cut grading for each Carat weight size the price of each stone is determined through the use of complicated formulas, through tables as well as through reliance on expertise and experience . A Few Helpful Hints De Beers, the world leading diamond trading company, recommends a budget of approximately 2 months salary for a diamond engagement ring. Determine what is more important for you, a diamond of larger size with some compromise on the overall quality combination of cut, clarity and color or a smaller diamond of higher quality and beauty.