Largest Diamonds Ever Found and Current Ownership
The Cullinan Diamond, discovered in South Africa in 1905, remains the largest gem-quality rough diamond ever found at 3,106 carats. Today, its polished pieces are part of the British Crown Jewels and held in trust by the Royal Collection Trust, with valuation estimates exceeding several hundred million dollars. The Lesedi La Rona, a 1,109-carat stone recovered in Botswana in 2015, was sold by Lucara Diamond Corp to Graff Diamonds in 2017 for $53 million, and Graff has since cut and sold multiple high-profile stones from the rough. The Excelsior Diamond, once the world's largest known gem diamond at 995 carats, was discovered in 1893 in South Africa and subsequently broken up for polishing, with pieces now scattered across private and institutional collections worldwide. The Star of Sierra Leone, a 968.9-carat stone found in 1972, was purchased by Harry Winston and cut into several gems, with the largest polished diamond from the rough weighing 53.96 carats and held in a private collection.
In 2024, the Botswana government confirmed that the Karowe Mine continued to produce large gem-quality stones, with Lucara Diamond Corp operating the facility and selling major finds through private agreements and structured auctions. The Sewelô diamond, a 1,758-carat stone recovered at Karowe in 2019, was purchased by Louis Vuitton's parent company LVMH, marking a shift in how high-value rough diamonds are acquired by luxury brands. The Constellation, an 813-carat stone also from Karowe, sold for $63.1 million in 2017 and remains one of the largest gem-quality diamonds ever auctioned. These transactions show a trend of sovereign nations and large corporations retaining or directly selling major stones, bypassing traditional auction houses for private deals.
Where the Biggest Diamonds Are Now and How They Are Stored
Vaults, Museums, and Sovereign Reserves
Major polished diamonds from historic stones are held in secure vaults operated by institutions such as the De Beers Group, which maintains high-security facilities in Botswana and South Africa for sorting, grading, and storing rough and polished inventory. The British Crown Jewels, including the Cullinan I Great Star of Africa at 530.2 carats, are displayed at the Tower of London under armed guard and managed by Historic Royal Palaces. The Smithsonian Institution in Washington, D.C. houses the Hope Diamond, a 45.52-carat deep blue diamond, as part of its National Gem and Mineral Collection, with the stone on permanent public display. Private vaults in Geneva, Antwerp, and New York also store large polished diamonds acquired by collectors, families, and sovereign wealth funds, with exact inventories undisclosed for security reasons.
Sovereign governments increasingly treat large diamonds as strategic assets, with Botswana's Department of Geological Survey overseeing the country's diamond wealth and the government retaining a majority stake in Debswana, the joint venture mining company. The Botswana National Museum and the Botswana Diamond Trading Company support the country's role in the global diamond supply chain, while the government has invested in cutting and polishing facilities to capture more value domestically. In Russia, the Diamond Fund at the Moscow Kremlin holds the 398.72-carat Red Spinel and other large stones, managed by the state corporation Rosatom, with the collection restricted from public access except for curated exhibitions.
How Auction Prices and Market Demand Shape the Diamond Industry
Record Sales and Price Drivers
Auction records for large colorless diamonds have been set repeatedly in the past decade, with the 163.41