Salesite

specimen number:
1655504

location:
Chuquicamata Mine, Antofagasta, Chile

description:
Nice for the species, bluish green micro crystals and massive across the front of matrix.

Chuquicamata, located in the Atacama Desert of northern Chile, is one of the largest open-pit copper mines in the world and a site of immense geological significance. The deposit is a classic porphyry copper system associated with a series of Eocene to Oligocene aged granodiorite and quartz monzonite intrusions. These igneous bodies were emplaced along the West Fissure fault system, a major crustal structure that facilitated the flow of metal-rich hydrothermal fluids into the surrounding rock. This resulted in a massive zone of mineralization characterized by disseminated copper sulfides and complex alteration patterns. Historically, the site has been worked for centuries, dating back to pre-Columbian times when indigenous peoples extracted copper for tools and ornaments. Modern industrial mining began in 1915 under the Chile Exploration Company (Anaconda), and the mine was later nationalized in 1971, currently operated by the state-owned company Codelco. In 2019, the mine began a historic transition from a century of open-pit extraction to large-scale underground block caving to access deeper ore reserves.

Salesite is a rare and striking copper iodate mineral that was first discovered at the Chuquicamata mine, which serves as its type locality. It typically forms in the highly oxidized zones of copper deposits where unusual environmental conditions allow for the concentration of iodine. The mineral is prized by collectors for its beautiful deep blue to bluish-green color and its distinct orthorhombic crystal habit, often appearing as stout prismatic crystals or as crystalline crusts and aggregates. It possesses a vitreous luster and is translucent to transparent in thin sections. Geologically, salesite is created when primary copper minerals are broken down by oxygenated waters in an arid environment, reacting with available iodine sources to precipitate this rare secondary species.

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