Malachite

Malachite from L'Etoile du Congo Mine, Lubumbashi, Katanga, Democratic Republic of the Congo, measuring 77 × 65 × 25 mm and weighing 240 grams. A flattish, broad piece of copper carbonate from one of the most historically significant mines in the Central African Copperbelt.

Malachite is copper carbonate hydroxide, Cu2CO3(OH)2, instantly recognisable by its banded or botryoidal green habit, and it forms in the oxidised zone of copper deposits where weathering carbonates and hydroxides replace the primary copper sulfides nearer the surface. The Katanga Copperbelt, straddling the southern DRC and northern Zambia, holds one of the largest copper-cobalt resources on Earth, hosted in Neoproterozoic sedimentary rocks, and its oxidised zones have produced some of the finest Malachite specimens ever found.

L'Etoile du Congo, near Lubumbashi, was among the very first mines opened in the Katanga copperbelt in the early twentieth century and has a long history supplying both copper ore and mineral specimens to collectors. Congo Malachite of this kind, showing the species' characteristic colour and texture well, remains a cornerstone of any copper-mineral collection. This piece is from the David Vince Collection.