Editor’s Note
This article details the discovery of an exceptionally rare natural Type IIb blue diamond at South Africa’s Cullinan mine. Prized for its intense color and excellent clarity, such stones represent a tiny fraction of all diamonds.

A natural Type IIb blue diamond, an extremely rare group accounting for less than 0.1% of all natural diamonds, was discovered at the Cullinan mine in South Africa. The diamond possesses an intense blue color and its clarity is described as “excellent” in both color and transparency.
According to the diamond mining company Petra Diamonds, this blue diamond weighs 41.82 carats, and its blue color is due to the element boron within its carbon structure.
Although the company has not yet published an estimated price, analysts believe that based on historical precedents such as the 39.34-carat blue diamond that sold for approximately $40 million in 2021, the new Cullinan gem could easily reach or exceed the $40 million mark, depending on its quality after cutting and market developments.
This event has given new life to the Cullinan mine, a site that has been part of global jewelry industry history since 1905 with the discovery of the largest rough diamond ever found.
Amid intense competition from synthetic diamonds and global economic fluctuations in the natural diamond mining industry, the 41.82-carat blue diamond promises to soon become the centerpiece of the world’s most prestigious collections or museums, further solidifying South Africa’s unique position on the global gemstone map.