This is an excellent specimen of superbly defined Dioptase lining a large vug in Malachite-bearing matrix. The Dioptase is highly lustrous, sharp edged and almost excellent terminated. The multifaced crystals are partly showing solution phenomena. This is classic Congo stuff from the heydays of this great mining area. A super colourful specimen in splendend condition with only minor imperfection from Renéville near Brazzaville in the Republic of the Congo.