The Victorian-era town of Cullinan, founded to support the Cullinan Mine, recently recovered a 41.82-carat blue diamond.
The town of Cullinan in the Gauteng province of South Africa was established in 1902 following the discovery of diamonds in the area.
It is located east of Pretoria along the diamond route. The town is named after diamond magnate Sir Thomas Cullinan.
The small town is popular for the 1905 discovery of the Cullinan Diamond, the largest gem-quality rough diamond ever found.
This diamond remains the largest gem-quality rough diamond ever found, weighing 3,106 carats, which is about 621 grams—roughly the size of a human fist.
The Cullinan Diamond was gifted to King Edward VII and later cut into several large stones. These stones are now the centrepieces of the British Crown Jewels:
- Cullinan I (The Great Star of Africa): At 530 carats, it is the largest clear-cut diamond in the world and is set in the Sovereign’s Sceptre with Cross.
- Cullinan II (The Second Star of Africa): This 317-carat cushion-cut diamond is the main stone in the Imperial State Crown, which the British monarch wears during the State Opening of Parliament.
While many mines produce white diamonds, the Cullinan Diamond Mine (formerly known as the Premier Mine) is the world’s most significant source of Type IIb blue diamonds.
These diamonds are incredibly rare and highly valuable due to their unique chemical composition, which contains boron.
The town of Cullinan itself serves as a living museum because it was built specifically as a company town for the mine, designed with an Edwardian and Victorian aesthetic.
Unlike many other South African towns that have modernised, the centre of Cullinan has been strictly preserved.
The main street, Oak Avenue, is lined with oak trees and original stone cottages that now house art galleries and cafes, making it a major destination for heritage tourism.
The McHardy House Museum, constructed in 1903, is the first house built in the town for William McHardy, the mine’s first manager.
The house has been preserved to reflect its original condition, offering visitors a glimpse into the lifestyle of the “elite” during the diamond rush.
St. George’s Anglican Church, designed by the renowned architect Sir Herbert Baker—who also created the Union Buildings in Pretoria—features a simple stone architecture.
On select weekends, vintage steam locomotives travel from Pretoria to the Cullinan Train Station, providing a nostalgic way to arrive in the town.
Petra Diamonds recovers 41.82-carat blue diamond
In January 2026, Petra Diamonds recovered a 41.82-carat blue diamond from its Cullinan mine in South Africa, which is believed to be of exceptional quality.
Although the stone is still undergoing detailed analysis, one dealer estimates it could sell for more than R500 million.
This diamond is classified as a type IIb blue diamond, recognised not only for its intense colour but also for its extreme rarity.
Most of these diamonds have been uncovered in the 120-year-old Cullinan mine, which has also produced some of the most famous diamonds ever discovered.
In the past five years, Petra has reported an annual production of between 1.4 and 1.9 million carats of diamonds.
The mine, discovered in 1902, is expected to continue producing gemstones until the 2040s. It is well-known in the industry for its rare blue diamonds.
Notably, it previously produced the De Beers Cullinan Blue, which was sold in 2022 for $57.5 million.
Additionally, a similarly sized 39-carat rough blue diamond found at the mine in 2021 eventually sold for over $40 million. This recent find marks the first significant recovery of a blue diamond at Cullinan since then.
Grant Mobley, editor and gemologist at Only Natural Diamonds, describes the stone as “one of the rarest finds on earth” and predicts that it could break records once its final value and size are confirmed.
