Where Do The Prices For “Price Per Carat” Come From?

When discussing diamonds, the word carat is always thrown around, and it’s often something we don’t understand especially when it comes to pricing. If you didn’t know already, the higher the carat, the more expensive the diamond will cost. The question that you might be wondering though is where are the prices for “price per carat” derived from?

The prices for “price per carat” are derived from price sheets by Rapaport, created by Martin Rapaport. The Rapaport Report classifies diamonds weighing between 0.01 to 5.99 carats and displays a price for any combination of the carat, color, cut, and clarity (the four c’s). Jewelers around the world follow the price list in the Rapaport Diamond Report.

The prices of diamonds can change from week to week; therefore, the Rapaport Diamond Report is updated each week with any changes to the diamond market. The report can be accessed by a paid subscription only.

Beyond4cs.com confirmed that some people see the Rapaport price sheets as not accurate anymore. This is due to it not taking into account the qualities of the diamond, such as the grading lab certifying the diamond, fluorescence, etc. Many of the other factors which now all determine the price of a diamond.

Who is Martin Rapaport, and why does he influence the pricing of diamonds?

Martin Rapaport started as a diamond cleaver apprentice in Belgium, then moved to New York City in 1975 where he was brokering rough and polished diamonds. It was in 1978 where he invented the Rapaport Price List. He has kept his career revolving around diamonds and created several businesses.

These days, many businesses follow the Rapaport report; this is because Martin Rapaport very much influences the global market and is seen as one of the most authoritative people in the diamond trade.

What is the definition of a carat, and what is the average price per carat?

Shiningdiamonds.co.uk states that a carat is a unit of measurement for the weight of a diamond. It does not refer to the surface area or depth of the diamond, purely the weight. Therefore, a higher diamond carat weight will not result in a larger sized diamond.

If you are buying a one-carat diamond, you can expect to pay between $1,800 and $12,000, as discussed above this guideline is recommended from the Rapaport Pricing List. There is a big difference between the lowest and highest prices, but the price of a diamond not only depends on the carat, but the cost can also increase or decrease due to the following factors:


The cut of a diamond is determined by the shape and three factors, to see how successful a diamond interacts with light and this will decide whether the cut of the diamond is considered as excellent, very good, good, fair or poor. These factors are:

  • Brightness
  • Fire
  • Scintillation

The cut of a diamond is also the shape that the diamond might be. Some shapes will cost more than other shapes. For example, the Round Brilliant cut is more expensive due to the amount of rough diamond that is cut off. In comparison, something like the Emerald or Asscher cut diamonds cost significantly less.


With diamonds, there is a color-grading system, and it runs from D to Z. D to F being colorless, G to J being near colorless, K to M being faint, N to R being very light and lastly S to Z being light. These colors are invisible to the human eye unless you are a professional; however, the color scale does affect the quality and price of a diamond.


There are six categories when it comes to the clarity of a diamond; these are:

If you want to learn more about the meaning of these categories, 4cs.gia.edu has given explanations to each of them.

Flawless is the most expensive type of diamond and included would be the cheapest type.

Where are the prices for “Price Per Carat” Derived From?

You should now know where the prices for price per carat comes from. Martin Rapaport has had a considerable impact on the diamond industry, setting the pricing standards for each diamond carat but keep in mind the controversy that surrounds the Rapaport Pricing List, some consider it inaccurate due to many other factors.

If you are looking into purchasing a diamond, it might be worth looking into the Rapaport Report to understand what you could be charged; the prices might, however, be different for each retailer. Sometimes it is worth doing your research and having an understanding of why you might be paying a specific price.

Carl A. Jones, GIA GG

Carl A. Jones is a GIA Graduate Gemologist with over 20 years of experience in the diamond industry. He is an independent jewelry appraiser. He specializes in determining the value of diamonds and advising consumers on how to buy quality diamond jewelry.

You May Also Like