Diamonds

Rare ‘Mellon Blue’ Diamond Fetches $25.5 Million at Christie’s Geneva Market Reflects Shifting Demand for Coloured Diamonds

The legendary Mellon Blue Diamond a 9.51-carat fancy vivid blue, internally flawless gem sold for $25.5 million USD at Christie’s Magnificent Jewels auction in Geneva this week. The sale, held at the Four Seasons Hotel des Bergues, drew global attention from elite collectors and gem enthusiasts alike.

The Mellon Blue once belonged to renowned art collector Rachel Lambert “Bunny” Mellon, whose refined taste and cultural influence continue to shape the world of art and jewellery. Despite its exquisite pedigree, the price achieved represents a 22 percent decrease from its previous sale 11 years ago and a nearly 60 percent drop in real value when adjusted for inflation.

Originally auctioned at Sotheby’s in 2014 as part of Mellon’s estate collection, the diamond fetched $32.6 million USD, setting a world record for a blue diamond at that time. Adjusted for inflation, that sum equates to approximately $44.7 million in 2025.

Christie’s had estimated the gem between $20 million and $30 million, and the final sale once again highlighted the continuing prestige of exceptional coloured diamonds despite softer market conditions.

Rahul Kadakia, Christie’s Chairman of Global Luxury and President of Asia Pacific, remarked:

“It was a true honour to offer for sale the exquisite Mellon Blue Diamond here at Christie’s Geneva. It was another notable moment for Christie’s Luxury, evidencing the elite appetite amongst collectors for extraordinary and storied gems.”

The winning bidder, identified only as a collector from Hong Kong, continued the stone’s legacy of global fascination.

While the Mellon Blue once held the world record for a blue diamond, that benchmark has since been overtaken by two other remarkable stones:

The 14.62-carat Oppenheimer Blue, sold at Christie’s in 2016 for $57.5 million USD
The 15.10-carat De Beers Cullinan Blue, sold by Sotheby’s in 2022, also for $57.5 million USD

These historic sales underline the rarity and enduring appeal of fancy vivid blue diamonds, which represent less than 0.1 percent of all diamonds, and of those, fewer than 1 percent qualify as fancy vivid.

Bunny Mellon, who passed away in 2014 at age 103, was celebrated not only for her wealth being heiress to the Listerine and Mellon fortunes but also for her artistry and impeccable taste. She famously designed the White House Rose Garden and curated an impressive art collection that included two Rothko masterpieces, which together realised $76 million USD at auction.

When Christie’s announced the diamond’s return to auction earlier this year, Kadakia described the sale as a tribute to Mellon’s lasting influence, saying her legacy “elevates the Mellon Blue’s allure by tying it to her sophisticated aesthetic and cultural prominence.”

The auction itself was as heated as the competition literally with the auctioneer requesting the windows be opened mid-sale to cool the room as bidding intensified.

About DCLA: The Diamond Certification Laboratory of Australia (DCLA) is the official CIBJO-recognised diamond laboratory in Australia, specialising in independent diamond grading and certification. DCLA ensures the highest international standards of accuracy, integrity, and transparency in diamond evaluation.

Legendary 137-Carat Florentine Diamond of the Habsburgs Rediscovered in Canadian Bank Vault After a Century

The world of fine jewellery is abuzz with the remarkable discovery of the legendary “Florentine” diamond a 137-carat yellow pear-shaped gem once belonging to the imperial Habsburg family of Austria-Hungary. After more than a century of mystery, the fabled diamond has resurfaced, astonishing historians and gem experts alike.

According to reports in international media, descendants of Emperor Charles I and Empress Zita revealed that the diamond had been safely stored in a Canadian bank vault for 100 years, fulfilling a century-long vow of secrecy made by the late Empress. The revelation ends decades of speculation surrounding one of the most famous missing royal jewels in history.

A Jewel of Remarkable Provenance

The Florentine diamond’s story stretches back centuries. Believed to have once belonged to the Medici family of Florence, the stone later became part of the Habsburg crown jewels. Some historians suggest the gem was originally cut for Charles the Bold, Duke of Burgundy, before finding its way to the Habsburg treasury.

The diamond vanished in the aftermath of World War I, when Emperor Charles I fled Vienna following the collapse of the Austro-Hungarian Empire. Many assumed the gem was lost or stolen during the family’s exile, adding to its mythical reputation and inspiring numerous books, films, and conspiracy theories.

Hidden Under Royal Secrecy

New accounts from Habsburg descendants reveal that the diamond was never lost. When the family sought refuge in Canada during World War II, they secretly transferred the Florentine along with other royal jewels to a bank vault, acting on Empress Zita’s orders. Only her sons, Archdukes Robert and Rodolphe, were informed of its location, bound by her request for confidentiality until 100 years after Charles I’s death in 1922.

With the vow now fulfilled, Karl Habsburg-Lothringen, grandson of Emperor Charles I, alongside his cousins Lorenz and Simeon von Habsburg, have confirmed the diamond’s existence and plan to exhibit the gem publicly in Canada as a gesture of gratitude to the country that sheltered their family.

A Treasure Reborn

The 137-carat golden-yellow diamond, renowned for its striking pear shape and exceptional size, is considered one of history’s most significant gemstones. Its rediscovery resolves one of the great mysteries of the 20th century, marking an extraordinary moment in the history of royal jewels.

The news follows renewed global fascination with high-profile jewel thefts including the recent Louvre robbery, where thieves made headlines by stealing crown jewels from the Apollo Gallery using a truck-mounted cherry picker.

With the Florentine diamond’s reappearance, the world’s attention once again turns to the enduring allure of legendary gems and the fascinating histories they carry a reminder of the importance of certification, provenance, and preservation in the world of fine diamonds.

Verified Provenance and Diamond Expertise

The reemergence of the Florentine diamond highlights the crucial importance of authentic certification and traceable provenance in the world of rare and historical gems. As the official CIBJO laboratory for Australia, the Diamond Certification Laboratory of Australia (DCLA) upholds these same principles ensuring every diamond’s identity, quality, and history are verified through independent, internationally recognised grading standards.

From modern treasures to legendary jewels of royal heritage, DCLA remains Australia’s trusted authority in diamond certification, valuation, and provenance verification, preserving the integrity of the world’s most extraordinary stones.

Sotheby’s Geneva Showcases Exceptional Provenance and Record-Breaking Natural Diamonds

Each November, Geneva takes centre stage in the world of fine jewellery, and Sotheby’s 2025 High Jewellery and Royal & Noble Jewels sales reaffirm why the city remains its beating heart. This year’s auctions bring together a breathtaking display of natural diamonds, historical heirlooms, and masterful craftsmanship that celebrate centuries of artistry and provenance.

At the forefront of the Sotheby’s High Jewellery Sale is The Glowing Rose, an extraordinary 10.08-carat Fancy Vivid Pink diamond estimated at around USD 20 million. Its rare, “pure pink” hue—free from secondary tones—places it among the most valuable gemstones in existence. Comparable to celebrated stones such as the Williamson Pink Star and Pink Legacy, this exceptional diamond embodies the geological miracle of atomic distortion, which gives natural pink diamonds their ethereal glow. Stones of this size and purity are exceedingly rare, making The Glowing Rose the undeniable star of the season.

Colour remains the hallmark of this year’s Geneva sale. A pair of Fancy Vivid Yellow diamond earrings, weighing 38.66 and 38.88 carats, are expected to achieve between CHF 2,000,000 and CHF 3,800,000. Their radiant colour intensity and impressive carat weight represent the highest standards of fancy diamond grading. Equally captivating is a 4.50-carat Fancy Vivid Blue diamond, internally flawless and estimated at CHF 4,400,000 to CHF 5,800,000. The blue hue, caused by trace boron, adds to its rarity and appeal, offering collectors the coveted trifecta of exceptional colour, clarity, and size.

Among the coloured gemstones, a 7.69-carat “Royal Blue” Kashmir sapphire set in a ring-pendant combination by Van Cleef & Arpels is a standout. Revered for their velvety “sleepy” lustre, Kashmir sapphires are among the most desirable in the world, and this piece exemplifies the pinnacle of gemological beauty. Further artistry is showcased through a pair of sapphire, tsavorite garnet, and diamond earclips by JAR—vividly imaginative and estimated at CHF 300,000 to CHF 500,000—reflecting the contemporary genius of Joel Arthur Rosenthal.

The sale also includes signature creations by Van Cleef & Arpels, Cartier, Graff, and De Grisogono. Highlights include a 10.04-carat marquise-shaped D-colour diamond ring by Graff (VVS2 clarity, estimated CHF 320,000–560,000) and a De Grisogono ruby and diamond bombé ring featuring two step-cut diamonds (estimated CHF 55,000–75,000).

In tribute to a century of Art Deco design, Sotheby’s presents an array of geometric masterpieces from Cartier and Van Cleef & Arpels, embodying the symmetry and elegance that shaped modern jewellery aesthetics. Two private collections will also headline the event: one dedicated exclusively to Van Cleef & Arpels, and another—Aria of Jewels: The Collection of Antje-Katrin Kühnemann—featuring exceptional Cartier and De Grisogono pieces from the late philanthropist’s private trove.

The Royal & Noble Jewels: A Journey Through History

Complementing the High Jewellery Sale, Sotheby’s Royal & Noble Jewels auction unveils some of the most historically significant diamonds and heirlooms ever offered. Among them is a diamond brooch once owned by Emperor Napoleon Bonaparte, lost during his flight after Waterloo and later recovered by the Prussian Royal family. After more than two centuries in private hands, it now re-emerges for the first time at auction.

Also featured is a light pink diamond ring with royal lineage, once belonging to Empress Catherine I of Russia and later to Princess Neslishah Sultan, estimated between CHF 240,000 and CHF 400,000. A natural pearl and diamond jewel formerly owned by Cunegonde of Saxony (cousin of Louis XVI) carries an estimate of CHF 340,000 to CHF 500,000, while a diamond tiara with a wild roses motif from the Duchess of Portland (1774–1844) is expected to fetch CHF 100,000 to CHF 170,000.

Adding to the grandeur is a Cartier emerald and diamond necklace featuring an 11.78-carat Colombian emerald, commissioned in 1932, exemplifying Art Deco refinement and royal provenance.

Celebrating Provenance, Craftsmanship, and Natural Rarity

From Napoleon’s lost brooch to The Glowing Rose, Sotheby’s Geneva continues to highlight how exceptional gems transcend beauty—they embody heritage, artistry, and history. These November 2025 auctions remind the world that in fine jewellery, rarity, provenance, and craftsmanship remain the ultimate symbols of enduring value.

About DCLA
The Diamond Certification Laboratory of Australia (DCLA) is the official CIBJO-accredited laboratory for Australia, recognised for its expertise in diamond grading and certification. DCLA continues to support transparency and integrity within the global diamond trade, celebrating events such as Sotheby’s Geneva that showcase the brilliance and authenticity of natural diamonds.

Rockefeller Kashmir Sapphire could Fetch $2.5m

The Rockefeller Kashmir, an Art Deco ring that belonged to the late John D. Rockefeller 3rd and his wife Blanchette, is to appear in a sale of the couple’s vast art collection.

The Cartier features a 17.66-carat cushion faceted base pyramidal sugarloaf cabochon sapphire, with diamonds and carries a $1.5m to $2.5m estimate.

The ring was created around 1925 and has been in the Rockefeller family for three generations.

John D. Rockefeller 3rd inherited billions of dollars from the family’s Standard Oil empire, and was a prominent philanthropist.

The ring will be auctioned at Christie’s New York at the Magnificent Jewels event, during their December Luxury Week, on 10 December.

The collection of Asian art, jewelry, major American paintings and other heirlooms, was held by the couple’s daughter Sandra Ferry Rockefeller, who died in October 2024, aged 89.

Some of the sale proceeds will benefit her youth empowerment foundation.

Source: IDEX

Five More Arrests over Louvre Heist

Five more suspects were arrested on Wednesday night (29 October) in connection with the Louvre heist.

One is believed to be a member of the four-man team that carried out the raid, who was identified through DNA evidence and seen on CCTV footage.

The two suspects arrested earlier (on 25 October) have “partially admitted” their involvement in the crime, according to French investigators.

Napoleonic crown jewels valued at over $100m were stolen on Sunday 19 October just as the museum, in Paris, was opening to visitors.

The thieves used mechanical ladder to reach a second-floor balcony, cut through the display cases with power tools, then escaped on motorbikes.

Laure Beccuau, the public prosecutor in Paris, said there was currently no evidence to suggest the theft was an inside job. None of the those arrested worked at the museum.

The four-man gang who carried out the raid left behind a motorbike helmet which provided a crucial hair sample believed to be linked to one of the suspects, together with multiple DNA samples.

The Louvre, the most-visited museum in the world, has since moved the remaining crown jewels to a vault at the Bank of France.

Source: IDEX

De Beers Rough Sales Triple in Q3

De Beers sold $700m worth of rough diamonds across its two sights in the three months to 30 September – more than tripling the $213m recorded during the same period last year.

In the third quarter of 2024, the company held only one sight, having cancelled the August session due to weak demand.

During the Q3 2025 sights, specific assortments were offered at discounted prices. De Beers no longer provides sight by sight updates.

It noted that trading conditions “continued to be challenging,” although consumer demand for natural diamond jewelry remained broadly stable, particularly in the US.

The company said progress seen in the first half of 2025 was hindered by newly imposed US tariffs on diamond imports from India, according to its production report published on 28 October.

However, it welcomed the recent exemption granted for natural diamond imports from countries participating in “aligned partner” trade agreements, announced last month.

Meanwhile, quarterly production increased year-on-year by 38 per cent, to 7.7m carats, although it is down 5 per cent for the year to date (17.9m carats).

Production guidance for 2025 is unchanged at 20 to 23m carats.

Source: IDEX

Alrosa to Extract Gold as Byproduct of Diamond Mining

Alrosa to Extract Gold as Byproduct Mirny, in Russia's Sakha Republic.

Alrosa plans to extract gold from its diamond-bearing alluvial deposits in Mirny, in Russia’s Sakha Republic.

The move comes as demand for natural diamond continues to slide, and gold prices reach record highs.

Alrosa, Russia’s state-controlled miner, announced on Friday (24 October) that it was “considering extracting gold as a byproduct during diamond mining at the Mirny-Nyurba Mining and Processing Division”.

Gold was first found in the area in 2020 and Alrosa says a team of geologists has so far recovered 433kg of it.

The proposal is that gold will be recovered as a byproduct from diamond-bearing sands and placer deposits (accumulations of valuable minerals) in the Mirny area. Alrosa will use existing processing facilities.

In 2024, the company bought the Degdekan gold deposit in the Magadan region – in a notable departure from its core activity of diamond mining.

It said it would invest over $100m in the project, which is expected to produce about 3.3 tonnes of gold annually when it reaches full capacity around 2030.

Source: IDEX

Post-Tariff Slump in US Imports of Swiss Watches

Swiss watch exports to the US plunged by more than 55 per cent in September, in what the Federation of the Swiss Watch Industry Exports (FHS) described as a “huge correction”.

Foreign sales surged in the weeks before the US introduced a 39 per cent tariff on Swiss imports on 7 August, as manufacturers front-loaded shipments.

Since then exports to the US have slumped, down by 23.9 per cent in August and now by 55.6 per cent in September.

“Without this expected but nonetheless extraordinary development, Swiss watch exports would have grown by 7.8%,” the FHS said in its latest update.

Hong Kong and China both saw a marked reversal of fortunes, from double-digit declines in August to double-digit increases in September. But that wasn’t enough to outweigh the US plunge.

Total Swiss watch exports fell by 3.1 per cent during the month to CHF 2.0bn (USD 2.5bn). The UK became the single biggest buyer, with imports up 15 per cent to CHF 173m ($218m), an 8.7 per cent market share.

The overall decline took cumulative exports for the first nine months of the year to CHF 19.0bn (USD23.9bn), an overall decline of 1.2 per cent.

Source: IDEX

Napoleon’s Diamond Brooch Leads Sotheby’s Sale

Treasures that once belonged to Napoleon Bonaparte are to be offered for sale by Sotheby’s Geneva on 12 November.

Details of the auction were revealed on Friday (24 October), less than a week after the devastating raid on the Louvre, in which items from the French crown jewels, valued at over $100m, were stolen.

Highlight of the Royal & Noble Jewels Sale is Napoleon’s unique brooch featuring old mine and mazarin-cut diamonds that was pinned to his hat during the 1815 Battle of Waterloo.

At its center is a large oval diamond weighing 13.04 carats, surrounded by nearly 100 old mine-cut diamonds arranged in two concentric rows.

The brooch was seized by the victorious Prussian army as the defeated Napoleon fled.

It appears for the first time at auction with an estimate of CHF 120,000 to 200,000 (USD 150,000 to 250,000).

“In his haste to flee Waterloo, where his armies had been overwhelmed by the combined forces of the British and Prussian armies, Napoleon had to abandon some of his carriages when they got stuck in a muddy road a few miles away from the battlefield – including the carriage containing those precious belongings,” Sotheby’s said.

Three days later the brooch was presented to Prussian King Friedrich Wilhelm III as a battle trophy.

It remained within the House of Hohenzollern for centuries, and passed down to emperors of Germany. It has been part of a different private collection for the last few years.

Source: IDEX

Rare Half-Pink 37.4-Carat Diamond Unearthed in Botswana

A remarkable two-coloured natural diamond has been discovered in Botswana, astonishing experts with its size and formation. The gem half pink and half colourless weighs an impressive 37.41 carats and measures approximately 24.3 x 16 x 14.5 millimetres, according to the Gemological Institute of America (GIA).

The GIA describes the stone as having formed in two distinct geological stages. Sally Eaton-Magaña, Senior Manager of Diamond Identification at the GIA, explained that the pink section likely began as colourless before undergoing plastic deformation possibly caused by a mountain-forming event millions of years ago. This natural deformation altered the crystal lattice, giving rise to the diamond’s vivid pink hue. The colourless section, in contrast, appears to have formed later under more stable conditions.

Pink diamonds are among the rarest gems on Earth, prized for their beauty and scientific intrigue. Unlike coloured diamonds that owe their hue to trace elements or radiation exposure, pink diamonds result from structural distortions within the crystal lattice. This phenomenon must occur under highly specific pressure and temperature conditions too little deformation and the diamond remains colourless; too much and it turns brown.

“It’s a geological balancing act like Goldilocks,” noted Curtin University geologist Luc Doucet, referencing the fine threshold that determines a diamond’s colour outcome.

What makes this new discovery even more extraordinary is its size. While other bi-coloured diamonds have been documented, they are typically no larger than 2 carats. The 37.4-carat specimen from Botswana represents a significant leap in both scale and scientific importance.

The diamond was unearthed at Lucara Diamond Corporation’s Karowe mine, one of the world’s most productive sources of exceptional diamonds. The Karowe mine has previously yielded some of the most celebrated finds in modern history, including the 2,488-carat “Motswedi” diamond, the second-largest rough diamond ever recovered, and the 62-carat “Boitumelo” pink diamond.

This latest discovery further cements Botswana’s position at the forefront of the global diamond industry and provides scientists with another remarkable glimpse into the complex natural processes that create the Earth’s most coveted gemstones.