A study of the world’s largest diamonds has identified unusual iron-rich domains in the Earth’s mantle that are associated with the kimberlite magmas carrying these rare gems, researchers from the University of Cape Town report. The finding, based on olivine chemistry, provides a practical geochemical tool for diamond exploration: kimberlites with abundant iron-rich olivine show higher potential to host CLIPPIR diamonds—the class that includes the 3,106-carat Cullinan. The work also traces the diamonds’ origin to subducted oceanic crust recycled into the mantle transition zone, more than 400 kilometres deep.

In the resources sector, drill results from junior explorers reinforced the link between geological models and discovery. White Cliff Minerals reported a step-out intercept of 41.5 metres at 0.87% copper from its Rae project in Nunavut, Canada, extending the mineralised strike to 5.4 kilometres and suggesting a district-scale system. Australian Gold & Copper intersected 26 metres at 102 grams per tonne silver equivalent from 433 metres depth at its Achilles deposit in New South Wales, including a 2-metre interval of 770 g/t silver equivalent, demonstrating resource growth at depth. Both results, announced to the ASX, illustrate how systematic drilling continues to expand known mineral frontiers.

Separately, an international team of primatologists described a new species of colobus monkey, Colobus congoensis, from the Lomami River basin in the Democratic Republic of Congo. Known locally as ‘Likweli’, the monkey is distinguished by its small size, glossy black fur, and a striking orange-cream patch around the mouth. Genetic analysis indicates it diverged from its closest relative, Colobus satanas, approximately 4–5 million years ago, making it one of the oldest known splits within the colobus lineage. The species was documented through 114 field observations between 2018 and 2022, along with anatomical and genetic evidence. Researchers from Florida Atlantic University, Yale, and Congolese institutions propose listing it as endangered, citing a restricted range of roughly 1,700 square kilometres and threats from hunting and habitat loss.

The week also brought advances in astronomy and chemistry. Astronomers announced the first detection of an atmosphere on a potentially habitable exoplanet, though details remain preliminary. Radio telescopes in the Milky Way’s centre detected erythrulose, a sugar molecule, in interstellar cloud G+0.693-0.027—the first confirmed saccharide in space, supporting theories that prebiotic molecules can form and survive in such environments. A separate genetic study reconstructed the origins of 152 freed slaves on the island of St. Helena in the 19th century, adding a historical dimension to the week’s discoveries.