Azurite is a secondary mineral formed from the alteration of copper deposits, often associated with green malachite. It is composed of copper carbonate and, of all the blue minerals, is certainly the best known and appreciated by collectors. The crystals are shiny and vary in colour from pale to deep blue. The most valuable specimens come from the Tsumeb mines in Namibia (Africa), discovered in 1851 by the British Explorer Sir Francis Galton. One of the most precious specimens is the Newmont azurite, known for the perfection and large size of its crystals, which reach 15 cm in length.
