Diamond prices are calculated using the Rapaport Price List.
diamond prices examples above
Carat weight is on the top bar and color is on the side. As shown above, to find say the value of a 1-carat range SI1 clarity H color you must run a line across till their paths meet. To calculate these prices you must multiply the carat weight. 1 carat is the easiest of course because it literally equals what is listed. a 1.35 carat is multiplied by the $6,500 rate + 8,775 vs the 1 carat $6,500. This is how you calculate the prices. This is the pricing you typically see at retail stores.
Very Important! Please notice the lines separating certain blocks. For example colors, D,E, and F are in one bracket – G and H in another. VS1 and VS2 are in a separate bracket and so on. Each of those brackets represent a price jump some more dramatic than others.
Different shapes have Diamond Pricing
Above is a sample of round diamond pricing but that doesn’t carry over to princess cut diamond pricing. Take a look at this 1 carat SI 1 clarity H color Princess cut diamond for $3,340 vs this Round 1 carat SI1 clarity H color Diamond for $4,610. Many don’t understand why but the reason is simple. A diamond unpolished is called diamond rough. It looks much like a rock. To cut and polish a diamond, different shapes leave more unused diamond waste.
Visit this link to see a great article from Blue Nile on how Diamond Prices and shapes differ.