August 2025
The Imboo Emerald — An 11,685-Carat Giant Recovered at Zambia's Kagem Mine
On 3 August 2025, Gemfields announced the recovery of an 11,685-carat rough emerald from the Chama pit at its Kagem mine in Zambia — the largest single gemstone ever unearthed at the mine, believed to be the world's largest single-producing emerald operation. Named Imboo, meaning 'buffalo' in the local Bemba and Lamba dialects, the stone weighs 2.337 kilograms and displays an intense, verdant green touched with golden warmth.
Kagem, located in Zambia's Copperbelt Province, is 75% owned and operated by Gemfields in partnership with the Zambian government through the Industrial Development Corporation. The mine has produced numerous exceptional emeralds over its operational life, but Imboo represents a new benchmark for single-stone size. Adrian Banks, Gemfields' Managing Director of Product and Sales, described how even under the strong light necessary to illuminate a gemstone of this remarkable size, Imboo reveals an intense green with a clarity that captivates the eye. The stone was offered at Gemfields' high-quality emerald auction running from 25 August to 11 September 2025, and its new owner was offered the opportunity to deploy nanoparticle-tagging technology — courtesy of Gemfields' partner Provenance Proof — providing full traceability even after the stone has been cut and polished. Zambia is the world's second most important source of emeralds by value after Colombia, and the Kagem deposit has been instrumental in establishing Zambian emeralds as a distinct and valued category in the global market. The discovery of a stone of this magnitude confirms that the Kagem pegmatite still holds the capacity to produce material of extraordinary scale.