Editor’s Note
This article details the remarkable discovery of the ‘Imboo’ emerald at Zambia’s Kagem mine. Unearthed by geologist Dharanidhar Seth, the 500-million-year-old gemstone is noted for its exceptional size, intense color, and rare transparency—a true geological treasure.
A singular story begins at the Kagem deposit, where nature carved a block of history. It was geologist Dharanidhar Seth who made his way to the heart of the Chama pit and discovered this unique piece that had been waiting for light for 500 million years. The Imboo emerald reveals an intense green with golden hues that powerful light does not obscure, but rather enhances. That same light confirms its exceptional transparency, a rare trait in specimens of this size.
The name Imboo translates to ‘buffalo’ in local dialects and embodies strength, persistence, and community, symbols that reflect its natural magnitude. With an unprecedented weight at the site, it surpasses Insofu (‘elephant’, 2010), Inkalamu (‘lion’, 2018), and Chipembele (‘rhinoceros’, 2021), solidifying a tradition of remarkably large finds.
From August 25th to September 11th, 2025, Imboo will be the star of the high-quality emerald auction organized by Gemfields in Bangkok. This opportunity places a jewel with history, origin, and potential at the center of international markets.
An innovative element is added to this treasure: the option to apply Provenance Proof nanoparticle technology as a permanent traceability seal. This invisible fingerprint guarantees that, even after polishing, its origin in Kagem can never be concealed.
The geology that allowed its formation speaks of an extraordinary convergence of the Tri-Junction model. This meeting of structural domains created the ideal environment for crystallizing large emeralds, a situation reinforced by precedents like the Kafubu Cluster, a set of over 37,555 grams discovered in 2022.
Beyond its intrinsic value, Imboo opens doors to multiple high jewelry strategies. A complete suite formed by several high-quality gems from the same block is envisioned, or preserving a part as a relic for collectors while another becomes the centerpiece of museum pieces.
This find highlights the pivotal role of Gemfields as a global player in quality gems, a producer of around 25% of the world’s emerald supply, thanks to its operation in Kagem, along with the Montepuez ruby mine and other initiatives in rubies and sapphires.