Rare Blue Diamond Worth $40M Discovered in South Africa

Type IIb bluish diamond. Credit: Petra Diamonds

A uncommon bluish diamond weighing 41.82 carats has been recovered from the Cullinan excavation successful South Africa, with experts saying the chromatic could beryllium worthy much than $40 million. The institution operating the excavation described the diamond arsenic being of exceptional colour and clarity.

Grant Mobley, a gemologist and exertion astatine Only Natural Diamonds Watch & Jewelry, said the chromatic ranks among the rarest finds connected world and could acceptable a caller grounds erstwhile cutting and grading find its last worth.

The chromatic belongs to a classification called Type IIb, which accounts for astir 0.1 percent of each earthy diamonds, according to the Gemological Institute of America. Diamonds of this benignant signifier with boron contiguous successful their operation and astir nary nitrogen. It is the boron that produces the bluish color, arsenic it filters retired warmer wavelengths of airy and allows cooler bluish tones to dominate.

What makes highly uncommon bluish diamonds truthful scientifically unique

The institution said this is the archetypal important bluish chromatic pulled from Cullinan since a 39-carat unsmooth bluish diamond was recovered determination successful 2021 and yet sold for much than $40 million. The excavation has antecedently produced 2 different notable bluish stones.

The De Beers Cullinan Blue, a 15.10-carat diamond, sold astatine auction successful 2022 for $57.5 million, and the Blue Moon of Josephine, a 12.03-carat stone, sold successful 2015 for $48.4 million.

Petra Diamonds has recovered a uncommon bluish diamond from the Cullinan excavation successful South Africa. At 41.82 carats, the chromatic could interruption auction records erstwhile chopped and graded. pic.twitter.com/o1NOyYLxKB

— Tom Marvolo Riddle (@tom_riddle2025) March 27, 2026

The recently recovered diamond is inactive being analyzed, and its last worth volition not beryllium known until it is chopped and graded. Before immoderate cutting begins, specialists walk months studying the stone.

They request to recognize however colour sits wrong it and however the crystal is structured, truthful they tin program cuts that support arsenic overmuch value and colour saturation arsenic possible. A misjudged chopped connected a colored diamond of this prime tin outgo millions successful mislaid value.

Cullinan’s record-breaking past and the roadworthy ahead

Cullinan has a well-established spot successful diamond history. The mine, which opened successful 1902 and is expected to stay productive into the 2040s, produced the 3,106-carat Cullinan Diamond, the largest gem-quality chromatic connected record, which was aboriginal chopped into 9 large gems present held successful the British Crown Jewels. Petra reports yearly accumulation of betwixt 1.4 cardinal and 1.9 cardinal carats implicit the past 5 years.

The find comes arsenic the natural diamond marketplace faces unit from respective directions. Prices for one-carat earthy diamonds dropped arsenic overmuch arsenic 26 percent betwixt 2022 and 2025, according to Rapaport, driven by the increasing popularity of lab-grown diamonds, reduced user spending, declining wedding rates, and commercialized pressures.