Beauty of Blue: Ultimate Guide to Buying Blue Diamonds

Brief History of Blue Diamonds

The earliest known blue diamonds were found in the Kollur mine in the😼 Golconda region of India. Famous blue diamonds from this region include the Idol’s Eye (15th century) and the Hope Diamond (17th century). Historically, blue diamonds were recovered mainly in India and Brazil. For the last 100 years, they have also been randomly and sporadiℱcally found in the Premier Mine (since renamed the Cullinan Mine) in South Africa. Blue diamonds make up less than 0.02 percent of all natural mined diamonds. Like other colored diamonds, blue diamonds are valued based on the clarity and intensity of the color first, followed by the size and finally the cut quality.

Blue diamonds are among the rarest colored diamonds. Blue diamonds get their color from the element boron but nitrogen also plays a role in determining the inten🔜sity of the color. The Boron replaces some of the carbon 💦in the diamond crystal structure and can produce anything from a very light hint of blue to a deep dark blue color.

Blue diamonds are mined Cullinan Mine in Sout🤡h Africa and Orapa Mine in Botswana. The🌌 Argyle Mine in Australia was also a source of high quality blue diamonds until it closed in 2020.

Blue Diamond Grading

A blue diamond is graded and classified based on several key criteria like white diamonds including color, clarity, cut, and carat weight. Color grading of blue diamonds is the most important aspect influencing pricing for a blue diamond. Colors are classified by the hue or the actual color of the diamond including secondary hues such as🌳 greenish-blue, grayish-blue and violet-blue. Tone is another factor that can vary from very light to very dark. Finally the saturation is the strength of the color. A blue diamond with high saturation or more vivid are more desirable in the market. Clarity, cut and carat weight grading is the same as other diamonds.

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

Faint Blue
Very Light Blue
Light Blue
Fancy Light Blue
Fancy Blue
Fancy Intense Blue
Fancy Vivid Blue
Fancy Deep Blue

Blue diamonds that are graded Fancy Vivid Blue and Fancy Deep Blue are the most intense in color and are also the most coveted. Fancy Vivid specifically describes a blue diamond that is medium to dark in tone and strong to very strong in saturation. In a past GIA study of 462 blue diamonds, only 1% were Fancy Vivid.
Blue diamonds are also graded on a clarity scale similar to white diamonds from Flawless to Included. Cut grading is also similar to white dཧiamonds including the proportions, symmetry and polish. The most popular fancy shapes for blue diamonds include cushion, radiant, oval, and pear, as these enhance the color and minimize waste during cutting. Carat weight is also the same as white diamonds. Sotheby's recommends only buying blue diamonds with a GIA certificate.

Cutting Blue Diamonds

The cutting process for blue diamonds is not analogous to near-colourless diamonds, or any other coloured diamonds for that matter. Blue diamonds usually occur as irregular, asymmetrical crystals. The blue colour may also be unevenly distributed throughout the rough crystal. Therefore, careful study of the crystallographic directions of the rough, and the properties of the stone, 🍌are needed to bring out the full potential of its colour and overall appearance. A high level of experience and expertise are therefore needed to cut and polish a blue diamond. To achieve the best possible visual appearance, expert diamond cutters often make modifications to traditional cutting styles.

Blue Diamond Rings with Pink Diamond Accents

Favorite Blue Diamonds Sold at Sotheby's

Every year, Sotheby's has the opportunity to sell some of the rarest blue diamonds at often record breaking prices. Blue diamonds are sought after by collectors for their rarity and histo𝔉rical ties to royalty like the Hope Diamond and the Wittelsbach-Graff Diamond. Additionally blue diamonds have long been symbols of wealth and power and have been prominently set in crowns, scepters and royal jewelry for corཧonations, weddings and other royal celebrations.

Take a closer look at our favorite blue diam💃onds.

Blue Diamond ring — The Mediterranean Blue Cushion Modified Brilliant-Cut Fancy Vivid Blue 10.03 carats

The Mediterranean Blue, 17,860,000 CHF

168开奖官方开奖网站查询:The Mediterranean Blue sold for 17,860,000 CHF ($21.5 million) in May 2025. This extraordinary 10.03-c🌳arat cushion-modified brilliant-cut diamond was renowned for its striking Fancy Vivid Blue color and exceptional clarity. Mined in South Africa, it began as an impressive 31.93-carat rough before being meticulously transformed into its final cushion shape. The cutting process, which spanned over six months, was carefully documented, preserving a unique photographic record of the diamond’s remarkable journey. Classified as Type IIb, a rare category known for its distinctive blue hue, the Mediterranean Blue displayed an exceptional intensity of color and clarity, standing out as a remarkable example of nature’s artistry. Its sale marked a testament to the expertise and precision required to shape one of the world’s most coveted and rare colored diamonds.

Fancy Light Blue Diamond Ring 5.83 Carats, 1,206,500 CHF

This 168开奖官方开奖网站查询:Fancy Light Blue Diamond Ring sold for 1,206,500 CHF ($1.5 million) in May 2025. The ring featur🌞ed an exquisite 5.83-carat oval-shaped diamond of Fancy Light Blue color, accented by two heart-shaped diamond shoulders. Accompanied by a GIA report confirming its natural color and Internally Flawless clarity, the center stone stood out for its soft yet captivating hue. The two heart-shaped side diamonds, weighing 0.52 and 0.50 carats respectively, were also certified by the GIA as D color and Internally Flawless—adding to the ring’s overall rarity and elegance. This refined and romantic composition underscored the enduring appeal of colored diamonds in timeless settings.

Blue diamond necklace — Attractive Fancy Blue diamond pendent necklace

Fancy Blue Diamond Pendent Necklace 4.05 Carats, 952,500 CHF

This 168开奖官方开奖网站查询:Fancy Blue Diamond Pendent Necklace sold for 952,500 CHF ($1.1 million) in May 2025. Showcasing a beautifully cut 4.05-carat heart-shaped diamond of Fancy Blue color, the pendant was suspended from a classic cable-link chain measuring approximately 420mm in length. The diamond’s captivating hue and symmetrical ꦆheart shaﷺpe lent the piece both charm and sophistication. Accompanied by a GIA report confirming its Fancy Blue, Natural Colour, and Internally Flawless grade, the diamond was also classified as Type IIb—a rare and highly sought-after category of blue diamonds known for their exceptional purity and conductivity. The necklace offered a romantic yet refined expression of one of nature’s rarest treasures.

Toi et Moi Pear Shaped Fancy Intense Blue Diamond Ring, $930,000

In May, Sotheby's sold a Toi et Moi ring feat🐠uring a Fancy Intense Blue Diamond for 825,500 CHF ($930,000). The Pear Shaped Fancy Intense Blue Diamond👍 is 3.03 Carats, Natural Colour, I1 Clarity. The ring also features a pear shaped 2.82 carat white diamond that is D Color, VVS1 Clarity. This unique setting was all about the blue diamond and increasingly Toi et Moi rings are popular with modern brides as an alternative to the single solitaire engagement rings.

Fancy Grayish Blue Diamond 3.32 Carats, $720,000

In December, Sotheby's sold a 168开奖官方开奖网站查询:marquise fancy grayish blue diamond for $720,000. The natural diamond is 3.32 carats and SI1 clarityꦍ and is unmounted.

Fancy Intense Blue Green Diamond 3.02 Carats, $560,000

This 168开奖官方开奖网站查询:Fancy Intense Blue Green Diamond sold for 4.3 million HKD ($560,000) in Apℱril 2024. The Cut Cornered Rectangular Modified Brilliant Cut Fancy Intense Blue Green Diamond is 3.02 Carats, Natural Colour, VS1 Clarity. This Blue Green Diamond at 3 carats is rare in both size and secondary hue that makes this diamond a truly special stone.

Blue Diamond Price

The price of natural blue diamonds varies widely but in general are priced significantly higher than comparable clarity and carat weight white diamonds and other colored diamonds. Only about 0.02% of all diamonds that are mined are naturally blue. The🌳 Hope Diamond is the most famous blue diamond and is 45.2 carat fancy deep gr💜eyish blue Type IIb diamond valued at over $200 million.

The most expensive blue diamond sold by Sotheby's was in 2022 for $57.5 million. The 168开奖官方开奖网站查询:De Beers Blue diamond is a step cut 15.10 carat Fancy Vivid Blue, Internally Flawless and a Type IIb diamond. The 168开奖官方开奖网站查询:six most expensive blue diamonds sold at auction have ranged from $25.8 million to $57.﷽5 million.

The price for a 1 carat blue diamond can range from $30,000 to $50,000 for Faint Blue to over $1 million for a Fancy Deep Blue diamond. A 168开奖官方开奖网站查询:1.01 Carat Fancy Gray Blue Diamond sold for $190,000 in 2021 while a 168开奖官方开奖网站查询:1.0🉐8 Carat Pear Sh൩aped Fancy Vivid Blue Diamond sold for $930,000. Blue diamonds that are Fancy Intense Blue and higher color grade can easily ⛎exceed $1 million per carat.

Buy and Sell Blue Diamonds at Sotheby's

Sotheby's often has impressive blue diamonds available at auction, including fancy intense and fancy vivid blue diamonds. If you don't want to wait until the next auction, Sotheby's also has a curated selection of high quality 168开奖官方开奖网站查询:blue diamonds available for immediate purchase. If you would like to source a special High Jewelry blue diamond ring or other blue diamond jewelry, a salon specialist would be happy to assist. Sotheby's also provides custom high jewelry services and custom engagement ring services with loose blue diamonds. Sotheby's is able to source rare and impressive blue diamonds from its global supplier network so contact a salon associate or specialist for more details. Sotheby's is always sourcing the most exquisite blue diamonds.