The Kafubu area, also called the Ndola Rural Emerald Restricted Area, is the principal emerald-producing district in Zambia, in the Copperbelt Province. It hosts the Kagem mine, the largest single emerald operation in the world, along with several smaller producing operations and a significant artisanal sector. The Kafubu deposits, together with the Colombian and Brazilian fields and the more recent Ethiopian discoveries, form the four most important emerald sources in the modern global trade.

Geological setting

The Kafubu emeralds occur in a series of beryllium-bearing pegmatites and quartz veins that intruded into Cr-bearing talc-magnetite-actinolite schists during the late Proterozoic, around 500 million years ago. The chromium content of the host rocks gives the Kafubu emeralds their characteristic strong green colour, with a slight bluish modifier in the better material. The Kafubu deposits are bounded by the Kafubu River, which gives the area its name, and cover roughly 100 square kilometres of the Ndola Rural area.

Production history

Commercial emerald production in the Kafubu area began in the 1970s, with significant operations developed in the 1980s and a major expansion in the 2000s under Gemfields, the international coloured-stone mining company. The Kagem mine, jointly owned by Gemfields and the Government of the Republic of Zambia, produces several million carats of emerald per year and supplies the bulk of Zambian emerald exports. Other Kafubu operations include the Grizzly Mine, the Pirala Mine and a number of smaller producers, alongside an artisanal sector that has historically been prone to conflict with licensed operations.

Material characteristics

Kafubu emeralds typically show a slightly bluish-green colour, more saturated than most Brazilian material and slightly cooler than Colombian Muzo or Chivor production. Inclusions are common and follow patterns characteristic of biotite mica, magnetite and two-phase fluid inclusions, which are diagnostic for Zambian origin in laboratory testing. Heat treatment is rare. Oiling and resin filling, in line with international emerald-treatment practice, is common.

Trade significance

The Kafubu area is the world's most consistent producer of commercial-grade emerald in the lower price points and a significant producer of fine material at the upper end. The Gemfields Kagem auctions, which sell the bulk of Kafubu output in Singapore and elsewhere, are the principal price-discovery events in the emerald market and are closely watched by the international coloured-stone trade. Kafubu material is the default Zambian reference in modern coloured-stone discourse, and its characteristic inclusion patterns are a key element in country-of-origin determination by laboratories such as GIA, SSEF and Gübelin.