Gemfields, which mines emeralds and rubies in Zambia and Mozambique, has put a giant emerald it extracted from the former for sale.

The AIM- and JSE-listed group said in a release on August 26 that the 11,685-carat (about 2.3kg), Imboo, is being displayed for sale at its auction that opened on August 25 and ends on September 11.

Imboo, which means buffalo in the Bemba and Lamba languages spoken in northcentral Zambia, is the latest, and largest, exceptional gemstone discovered at Kagem Mining (Kagem).

“Even under the beam of a strong light that is necessary to illuminate a gemstone of this remarkable size, Imboo reveals an intense, verdant green touched with golden warmth and a clarity that captivates the eye,” said Adrian Banks, Gemfields’ Managing Director – Product and Sales.

Located in Zambia’s Copperbelt Province, Kagem is 75% owned, and operated, by Gemfields, in partnership with the Zambian government through the Industrial Development Corporation.

"The new owner of Imboo will be offered the opportunity to deploy unique nanoparticle-tagging, courtesy of Gemfields’ longstanding partner Provenance Proof," said Gemfields in the statement.

"Providing full traceability of the gemstone, even after it has been cut and polished, Provenance Proof enables future owners to be certain that their gem originated from Kagem – and that it was part of this historical find."

Apart from Kagem, Gemfields is also the operator and 75% owner of the Montepuez ruby mine in northern Mozambique.

Gemfields holds controlling interests in various other gemstone mining and prospecting licences in the two countries as well as in Ethiopia and Madagascar, also in Africa.