Petra Diamonds has unveiled the discovery of a remarkable 41.82-carat blue diamond at South Africa’s legendary Cullinan Mine, reaffirming the site’s status as one of the world’s most important sources of rare blue stones.
Celebrated for its vivid colour and exceptional clarity, the diamond belongs to the elusive Type IIb category—stones so scarce they account for only a tiny fraction of global diamond production. Cullinan has historically yielded some of the most valuable blue diamonds ever sold, many commanding record-breaking prices per carat on the international auction circuit.
Blue diamonds form under extraordinary geological conditions, originating more than 500 kilometres beneath the Earth’s surface. Their distinctive hue is created by trace amounts of boron, a feature that sets them apart both scientifically and commercially. According to industry data, these diamonds have demonstrated strong long-term value growth, with blue diamonds recording a +242% appreciation since 2005.
Beyond rarity and value, such discoveries also carry wider economic significance. The Natural Diamond Council highlights that responsible diamond recovery ensures a large share of generated value remains within producing countries, supporting employment, public infrastructure, education, healthcare, and social development initiatives, alongside contributing vital tax and royalty revenues.