Discover the 6 Most Expensive Blue Diamonds

Blue diamonds are among the most mesmerizing and coveted gemstones in the world, known for their rarity and stunning beauty. These extraordinary diamonds, which range in hues from light blue to deep, rich tones, captivate the imagination of collectors and gem enthusiasts alike. Throughout history, blue diamonds have held a special allure, often symbolizing wealth, power, and mystery. In this article, we’ll explore the fascinating origins of blue diamonds, the unique characteristics that define their value, and introduce six of the most expensive and rare blue diamonds ever discovered.

Early History of the Blue Diamond

The origins of the blue diamond can be traced back to the Kollur mine in India’s Golconda region, where some of the first famous blue diamonds were unearthed. Renowned diamonds such as the Idol’s Eye (15th century) and the Hope Diamond (17th century) were among the earliest to capture the world’s attention. Historically, these diamonds were primarily sourced from India and Brazil. However, over the last century, blue diamonds have also been found sporadically in South Africa’s Cullinan Mine, which continues to produce rare stones to this day.

While blue diamonds are incredibly rare—making up less than 0.1 percent of all diamonds—what sets them apart is their sheer beauty. Unlike other colored diamonds, blue diamonds can grow much larger, with red diamonds typically only reaching up to 1 carat in size. The distinctive blue color comes from the presence of boron within the diamond’s crystal structure, though nitrogen also plays a role in intensifying the hue. This results in a spectrum of blues, from a faint light blue to an intense, almost otherworldly deep blue.

These diamonds hold a unique fascination for collectors due to the complexities involved in their creation and cutting. Achieving an evenly distributed and pure blue color is a difficult challenge, requiring skilled craftsmanship to enhance the natural beauty of the stone. The result is a gem that sparkles with an unmatched radiance, often taking months to perfect

Blue Diamond Grading

Like all diamonds, blue diamonds are graded according to four main criteria: color, clarity, cut, and carat weight. However, when it comes to blue diamonds, color plays the most significant role in determining the diamond’s value. The Gemological Institute of America (GIA) categorizes blue diamonds based on several factors, including the hue (which can range from a subtle blue to a more intense blue-gray), tone (from light to dark), and saturation (how vivid the color appears).

Blue diamonds are graded on a scale from Fancy Light Blue to Fancy Dark Blue, with the most prized stones being classified as Fancy Vivid Blue. These diamonds exhibit the strongest saturation and most intense blue hues. In fact, only 1% of all blue diamonds fall into this coveted Fancy Vivid category, making them some of the most sought-after gems in the world.

The Gemological Institute of America (GIA) uses the following categories to describe the color of blue diamonds:

Fancy Light Blue
Fancy Blue
Fancy Intense Blue
Fancy Vivid Blue
Fancy Deep Blue
Fancy Dark Blue

Blue diamonds that are graded of Fancy Vivid Blue are the most prized stones. These diamonds exhibit the strongest saturation and most intense blue hues. In fact, only 1% of all blue diamonds fall into this coveted Fancy Vivid category, making them some of the most sought-after gems in the world.

Type IIb Blue Diamond

The Type II classification refers to diamonds with minimal or no nitrogen impurities, giving them exceptional clarity and transparency. Type IIb diamonds are even rarer, as they contain boron, which imparts the blue or grayish-blue color. This unique composition not only enhances their striking hue but also makes Type IIb diamonds semiconductors, capable of conducting electricity—an unusual property for diamonds.

Among the rarest and most prized of all blue diamonds, Type IIb stones include iconic gems such as the Hope Diamond. These diamonds are highly coveted by collectors for their exceptional beauty, rarity, and distinctive electrical properties.

Cutting Blue Diamonds

The cutting process for blue diamonds is a delicate art, vastly different from that of near-colorless diamonds or other colored stones. Blue diamonds typically form as irregular, asymmetrical crystals, with their blue color often unevenly distributed throughout the rough. To reveal the full potential of the stone, expert diamond cutters must carefully study the crystallographic directions and properties of the rough diamond, ensuring that the final cut enhances both its color and overall appearance.

To achieve the most stunning result, cutters often adapt traditional cutting techniques. A perfect example is the cushion cut, a preferred choice for blue diamonds. This shape not only highlights the diamond’s captivating Vivid Blue hue but also complements the stone’s natural beauty with its classic, elegant form. The harmoniously softened edges of the cushion shape allow the blue color to shine, offering a timeless appeal that connects the diamond to some of the most iconic gems in history.

Most Famous Blue Diamond: The Hope Diamond

Perhaps the most famous blue diamond in the world, the Hope Diamond is a remarkable 45.2-carat Fancy Deep Greyish Blue Type IIb diamond, valued at over $200 million. The diamond’s storied history dates back to the 17th century when it was first acquired in India by French gem merchant Jean-Baptiste Tavernier. Initially weighing 112 carats, the stone was eventually cut into a 69-carat gem and became part of the French Crown Jewels. After its disappearance during the French Revolution, it reappeared in London in the early 19th century.

The Hope Diamond was then recut to 45.52 carats and is named after its later owner, Henry Philip Hope. It was sold to Harry Winston in 1949, who donated it to the Smithsonian Institution in 1958, where it remains on display today as one of the most famous gemstones in history.

6 Most Expensive Blue Diamonds

Sotheby’s has had the privilege of auctioning some of the world’s most extraordinary and expensive blue diamonds. From record-breaking sales to unforgettable pieces with historical significance, these six blue diamonds exemplify the peak of luxury and rarity in the world of fine gemstones.

1. De Beers Blue, $57.5 million

The De Beers Blue diamond achieved a record-breaking sale of $57.5 million at Sotheby's in April 2022, making it the most expensive blue diamond ever sold at auction. Weighing an extraordinary 15.10 carats, this Fancy Vivid Blue diamond is not only the largest of its kind to ever appear at auction, but it is also the largest internally flawless step-cut vivid blue diamond ever graded by the Gemological Institute of America (GIA). The diamond was cut from an exceptional rough stone discovered in April 2021, further enhancing its rarity and prestige. With a saturated blue hue, combined with its Internally Flawless clarity, the De Beers Blue is a true marvel of nature, setting a new benchmark for blue diamonds at auction.

Graded Fancy Vivid Blue by the GIA, the De Beers Blue ranks among the top 1% of all blue diamonds ever submitted for evaluation. Its clarity grade of Internally Flawless, coupled with the rare Type IIb classification, makes it an exceptionally rare find, with less than 0.5% of all diamonds falling into this category. The diamond’s flawless qualities are complemented by its classic step-cut, a style typically associated with white diamonds but highly coveted in rare colored diamonds. With its exceptional color, clarity, and size, the De Beers Blue represents a landmark moment in the world of fine gemstones, solidifying its place as one of the most extraordinary diamonds ever to grace the auction block.

2. Blue Moon of Josephine, $48.5 million

The Blue Moon diamond, a stunning fancy vivid blue gemstone weighing 12.03 carats, made history when it sold for a record-breaking $48.5 million at Sotheby’s in November 2015. Renowned as one of the rarest diamonds in the world, it holds the title for the highest price per carat ever achieved for a blue diamond, at just over $4 million per carat. The stone, exhibiting remarkable internal flawlessness, is a Type IIb diamond with a natural blue color, making it an extraordinary example of nature’s brilliance. The diamond’s acquisition by a private collector in Hong Kong marked the beginning of its rebranding as the "Blue Moon of Josephine," a name that underscores its rare beauty and allure.

Unearthed from the legendary Cullinan mine in January 2014 as a 29.62-carat rough stone, the Blue Moon diamond is one of the few stones to have been precisely tracked from its discovery through to its cutting. It was exhibited at the Natural History Museum of Los Angeles County from September 13, 2014, to January 6, 2015, further solidifying its place in the pantheon of iconic gemstones. The cushion-shaped diamond's vivid blue hue and exceptional clarity were matched only by its symbolic significance. Suzette Gomes, CEO of Cora International, aptly described the stone’s unique allure, saying, “Its shape is reminiscent of a full moon, and the metaphor for the expression is exactly what one could say about the occurrence and existence of such a gemstone.” This rare and iconic diamond is a true masterpiece in the world of fine jewelry.

The Apollo Blue Fancy Vivid Blue 14.54 carats and The Artemis Pink Fancy Intense Pink 16.00 carats — Apollo and Artemis Diamonds

3. The Apollo and Artemis Diamonds, $42.1 million

Sotheby’s auctioned a pair of colored diamonds, Apollo and Artemis, which became the most valuable earrings ever sold at auction, fetching an astounding total of $57,425,478 in May 2017. These exceptional stones, a blue diamond weighing 14.54 carats and a pink diamond weighing 16.00 carats, were mounted as earrings and offered separately due to their extreme rarity and overwhelming presence. The Apollo blue diamond, a Fancy Vivid Blue, is internally flawless and a Type IIb diamond, while the Artemis pink diamond is a Fancy Intense Pink with VVS2 clarity and a Type IIa classification. The blue diamond earring alone sold for an incredible $42.1 million, setting a new benchmark in the world of high-end jewelry.

These two extraordinary stones are perfectly matched in size, cut, and tonality, creating a striking balance of beauty and rarity. Described by David Bennett, Worldwide Chairman of Sotheby’s International Jewellery Division, as “by far the most important pair of earrings ever offered at auction,” the diamonds possess an unparalleled purity and luminosity. The Apollo, with its deep blue hue caused by the presence of boron, is part of the rarest category of diamonds, while the Artemis exudes a mesmerizing pink hue. Both diamonds were cut into lyrical pear shapes, and their names—after the revered Olympian deities—perfectly capture the majestic aura and cosmic wonder surrounding their creation billions of years ago. Together, they represent the epitome of nature’s most precious wonders, a testament to the unparalleled power and beauty of these remarkable stones.

The Zoe Diamond Fancy Vivid Blue Diamond Pendant 9.75 carats — The Zoe Diamond

4. The Zoe Diamond, $32.6 million

The fourth most expensive blue diamond, a stunning pear-shaped Fancy Vivid Blue diamond weighing 9.75 carats, sold for an impressive $32.6 million in 2014. This extraordinary diamond was part of the prestigious Collection of Mrs. Paul Mellon. After 20 minutes of intense bidding, Mrs. Mellon’s magnificent 9.75-carat diamond pendant—rare and exquisite—surpassed its high estimate by more than double. Certified by the GIA as a Fancy Vivid Blue, Natural Color diamond with VVS2 clarity, the stone also comes with the original working diagram, suggesting it may be potentially internally flawless. This captivating diamond was later renamed The Zoe Diamond, solidifying its place as one of the most coveted gemstones in the world.

5. De Beers Millennium Jewel 4, $32.2 million

Sotheby’s Hong Kong auctioned an extraordinary 10.10-carat internally flawless blue diamond for a remarkable $32 million in April 2016. This rare gem was part of the iconic De Beers Millennium Jewels collection, which was showcased alongside The Steinmetz Group to mark the turn of the millennium. The collection, featuring eleven exceptional blue diamonds, was exhibited at London’s Millennium Dome in 2000. The diamond, a natural Fancy Vivid Blue, is cut in an oval-modified brilliant shape and is inscribed with the mark "De Beers Millennium Jewel 4," a testament to its unparalleled quality and heritage.

The De Beers Millennium Jewels collection also became infamous due to the daring "robbery of the millennium." In an audacious heist, a ten-ton JCB digger smashed through the Millennium Dome’s wall, only to discover that the priceless diamonds had been replaced with replicas a day earlier in preparation for the robbery. Armed with sledgehammers, guns, and grenades, the thieves attempted to break through the gem’s armored casing but were quickly apprehended. Despite the heist's dramatic nature, the jewels' legacy as some of the most prized and coveted diamonds in history remains intact.

6. The Infinite Blue, $25.8 million

Sotheby’s sold the remarkable Infinite Blue Diamond for 198 million HKD, or $25.8 million in October 2023. This extraordinary 11.28-carat radiant-cut Fancy Vivid Blue diamond, featuring a natural color and VS2 clarity, is classified as a Type IIb diamond, one of the rarest and most coveted categories of diamonds. Accompanied by a monograph, the diamond’s exceptional rarity is underscored: "To say the Infinite Blue is special cannot be overstated. The odds of finding a blue diamond are among the most extraordinary in the world. This magnificent and remarkable gem exemplifies what happens when nature guides the way, and humankind cherishes the earth’s treasures—resulting in a stone that dazzles with spirited light performance.

Honorable Mention: The Mediterranean Blue

The Mediterranean Blue is an extraordinary 10.03-carat cushion-modified brilliant-cut diamond, renowned for its striking Fancy Vivid Blue color and exceptional clarity. Mined in South Africa, it was originally an impressive rough weighing 31.93 carats before being meticulously transformed into its current cushion shape. The diamond’s cutting process, spanning over six months, was carefully documented, preserving a unique photographic record of this rare blue diamond's journey. Classified as Type IIb, a rare category known for its distinctive blue hue, the Mediterranean Blue showcases a remarkable intensity of color and clarity, making it a standout example of nature’s artistry.

Accompanied by two GIA reports, this masterpiece is certified as Fancy Vivid Blue, with a VS2 clarity grade, affirming its superior quality. A GIA monograph describes the Mediterranean Blue as "a remarkable example of one of the rarest color sensations observed in a diamond." This diamond is a testament to the expertise and precision involved in shaping one of the world’s most coveted and rare color diamonds. The Mediterranean Blue will be featured in Sotheby's High Jewelry auction on May 13, 2025.

Blue diamonds remain among the most coveted and mesmerizing gemstones in the world, thanks to their rare beauty and historical significance. With origins tracing back to the renowned mines of India and South Africa, these diamonds continue to captivate collectors and gem enthusiasts alike. The sale of diamonds like the De Beers Blue, the Blue Moon of Josephine, and the Hope Diamond highlights the ongoing fascination with these exceptional gems, reinforcing their status as symbols of wealth, power, and elegance.

Advantages to Buying Blue Diamonds on the Secondary Market

There are many advantages to buying blue diamonds at Sotheby's. As one of the largest and most established global luxury secondary markets, Sotheby's offers clients many unique advantages when growing a diamond jewelry collection.

1. Access

Sotheby's is able to provide access to a curated selection of blue diamonds from its long established global network of sellers. Sotheby's is a leading global marketplace that offers pristine diamond jewelry in the most rare colored diamonds from an assortment of designers. Our jewelry specialists are always sourcing the more desirable diamond jewels from collectors around the world. Sotheby's also sells incredible private collections that include one of a kind blue diamonds.

2. Flexibility

Sotheby's provides multiple ways to purchase blue diamonds including auction, online and in person in New York, Hong Kong, Zurich, Paris and London. Sotheby's also offers a concierge service if you need assistance sourcing specific diamond jewels that aren't available at auction or online.

3. Value

As a leading global secondary market, Sotheby's often provides great value for blue diamonds. While Sotheby's regularly sells diamond jewelry over $600,000, many of these diamond jewels sell for below the original retail price. Signed diamond pieces can experience a 30 to 40% decrease from retail price to secondary market. Non-signed diamond pieces may fluctuate based on the current market price for the raw materials themselves. The discount varies depending on the jewelry's design, quality, size of the diamond and gem stones, and overall market conditions. Some diamond jewelry can also sell at a premium to the original retail, especially for one of a kind vintage designs, diamond jewelry with provenance linked to celebrities and/or royalty, and pieces featuring exceptionally rare diamonds and colored gem stones. Sotheby's is a great place to start collecting diamond jewelry. Sotheby's also provides seasoned collectors value for vintage diamond jewelry at prices that can be materially lower than retail replacement values.

4. Discovery

One of the best parts of a global luxury secondary market is discovering unique pieces from decades earlier and custom designed one of a kind diamond jewelry pieces. Sotheby's curated selection changes regularly and each auction has a unique selection of diamond jewelry. You are likely to discover something new to you.

Buy and Sell Blue Diamonds At Sotheby's

Sotheby's often has rare and collectible blue diamonds available at auction. Sotheby's also has a curated selection of diamond jewelry available for immediate purchase on marketplace. If you would like to view diamond jewelry, a salon specialist would be happy to assist. Sotheby's is also able to source diamond jewelry from its global supplier network.

Prices for diamond jewelry start around $4,000 for white gold and diamond band rings and rise significantly for more coveted diamonds. Iconic diamond rings, such as platinum diamond engagement rings can exceed $800,000.

Explore upcoming jewelry at auctions in New York, London, Switzerland, Paris, and Hong Kong.
Speak to a Salon Associate in New York, London, Paris, or Hong Kong to schedule an appointment.
Contact a Jewelry Specialist about selling a blue diamond.

Trust our worldwide network of leading jewelry specialists from a globally renowned auction house established in 1744.