Posted on January 7, 2015 by

Ask the Expert: Why Are Some Natural Blue Diamonds So Much More Expensive Than Others?

natural blue diamond

Dear Diamond Expert,


I noticed that some blue diamonds sell at auction for millions of dollars and the experts always say it’s because they’re so rare.  But I see blue diamond jewelry at jewelry chain stores all the time now, so are they really that rare?

-Jessica M. via email







Natural Blue Diamonds


1.07 carat Cushion Cut Fancy Intense Blue Diamond

A natural blue diamond, such as this 1.07 carat cushion cut Fancy Intense Blue diamond, is worth several dozen times more than the treated blue diamonds found in jewelry chain stores.


Dear Jessica M.,


That’s an excellent question you raise! While you are correct in pointing out that jewelry chain stores, such as Helzberg Diamonds, are popular purveyors of colored diamonds, such as the blue diamonds you’ve seen with your own eyes, there is a very glaring difference between the kind of blue diamonds you will find in chain retailers and the ones that are offered at auction via Sotheby’s and Christie’s. First and foremost, the ones sold by large auction houses will always be entirely natural, non-treated and non-enhanced. Their color has never been artificially altered by the hands of man. On the other hand, jewelry chains are known to carry colored diamonds that have been treated or enhanced by heating or irradiation. Diamonds that are treated or enhanced in any way are typically priced much lower than natural, non-treated colored diamonds and are therefore much more accessible to a wider swath of the consumer market. The World Jewellery Confederation and the United States Federal Trade Commission require that vendors provide full disclosure of all treated diamonds being sold.


Unlike treated blue diamonds, natural blue diamonds are some of the absolute rarest colored diamonds that can be found. Less than 1 percent of the overall diamonds mined annually consists of blue diamonds. Not surprisingly, blue diamonds over 5 carats are even rarer. Color in blue diamonds, as with all colored diamonds, is directly correlated to rarity and value: the stronger (i.e., more intense) the color, the rarer the blue diamond and thus the greater its value. Unlike blue diamonds that have undergone synthetic treatment, the color of natural blue diamonds is credited to the presence of boron impurities found in its crystal matrix as the diamonds are formed. The more boron particles that are present, the more intense the blue color will appear in the diamond.


So, Jessica, the very nature of the blue diamonds you’ve come across in mass chain stores determines their much cheaper and more widely attainable price point. Treated and enhanced blue diamonds are not in the same league as natural blue diamonds and their respective price points certainly reinforce their particular value.  To learn more about this incredible diamond color, read our guide to natural fancy blue diamonds.


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One Response to Ask the Expert: Why Are Some Natural Blue Diamonds So Much More Expensive Than Others?

  1. Jessica says:

    Thanks so much for featuring my question! I didn’t realize that some colored diamonds were actually “treated” to change their color! You learn something new every day ;)