Rare Blue Diamond Worth R660 Million Unearthed in South Africa

• A rare blue diamond discovered at the Cullinan Mine reminded many of South Africa’s deep-rooted place in the global diamond industry
• The stone’s rarity and potential value sparked renewed interest at a time when lab-grown diamonds continue to disrupt traditional markets
• Experts believe the diamond’s final value will depend on careful cutting and polishing decisions still underway

At a time when the diamond industry is under pressure, this discovery feels like a quiet statement from the earth itself, reminding the world that South Africa’s mines still hold treasures capable of reshaping global attention.

A rare blue diamond weighing just under 42 carats was recently unearthed at South Africa’s historic Cullinan Mine, about 20 miles east of Pretoria. According to Africa Business Insider, the stone was discovered by Petra Diamonds, the company that operates the mine, and early assessments suggest it could sell for as much as $40 million at auction. The diamond, officially measured at 41.82 carats, belongs to the ultra-rare type IIb category, which accounts for less than 0.1% of all natural diamonds. Specialists are still analysing the rough stone to determine how it should be cut and when it may eventually go to market.

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Type IIb diamonds are among the rarest gemstones on Earth, with their blue colour caused by trace amounts of boron formed deep underground. These stones develop at extreme depths and are only brought closer to the surface through volcanic activity over millions of years. The Cullinan Mine has long been associated with extraordinary finds, most famously the Cullinan Diamond discovered in 1905, which remains the largest gem-quality rough diamond ever found and now forms part of the British Crown Jewels.

Why this discovery matters for SA’s diamond legacy

The discovery comes at a challenging time for the global diamond industry. Natural diamond prices have faced pressure in recent years due to weaker demand and the rapid rise of lab-grown alternatives, which are often far cheaper. Despite this, experts believe rare coloured stones like this blue diamond still hold strong appeal for collectors and long-term investors.

Johannesburg diamond dealer Gregory Katz, speaking to News24, explained that while the finished polished stone would be significantly smaller than the original rough diamond, its quality and rarity could still place its value between R490 million and R495 million. He noted that cutters would aim to balance size, clarity and colour to maximise its final worth. The discovery comes as global diamond prices face pressure from lab-grown alternatives and weaker demand.

3 Other Briefly News stories related to diamonds

• The office of the KZN Premier reported a 'diamond rush' near a rural Ladysmith community, with many gathering in the hopes of collecting the precious stones.
• Sorisha Naidoo's husband, Vivian Reddy, recently surprised her with a massive diamond ring, prompting reactions online.
• South Africans online were left buzzing with speculation after noticing a big diamond rock on Anele Mdoda's left ring finger at a red carpet.

Source: Briefly News