Amazing Linarite Crystals

Amazing Rosette Linarite from Modrá štola, Zlaté Hory (Zuckmantel), Olomouc Region, Moravia (Mähren; Maehren), Czech Republic. Photo Copyright © Czechmin.cz

Linarite is a rare mineral known for its striking azure-blue color, making it a favorite among mineral collectors. This secondary copper lead sulfate mineral has the chemical formula PbCuSO₄(OH)₂, where lead and copper ions combine with sulfate and hydroxyl groups to form its crystalline structure. Linarite does not occur in large deposits but rather as small, often acicular (needle-like) crystals, clusters, or as coatings on other minerals.

This mineral forms under specific geochemical conditions, primarily as an alteration product of lead and copper sulfides. It's found in the oxidized zones of lead-copper deposits where sulfides have been exposed to oxygen and water over time, leading to the creation of new minerals. The process involves the sulfides reacting with oxygen to form sulfates and hydroxides, which combine with lead and copper to create linarite. This is why linarite is often found alongside other secondary minerals like malachite, azurite, brochantite, and cerussite, which are also indicative of an environment rich in copper and lead.

Linarite's crystal system is monoclinic, and it exhibits perfect cleavage in one direction along {100}, which can result in crystals that are brittle and easily damaged. Its hardness is relatively low at 2.5 on the Mohs scale, meaning it can be scratched by a fingernail. Despite its fragility, linarite's vitreous to sub-adamantine luster adds to its allure, reflecting light in a way that highlights its deep blue color.

Linarite : PbCu(SO₄)(OH)₂

Linarite was first identified in 1822. It is named after the Linares Plateau, Spain. It occurs in association with brochantite, anglesite, caledonite, leadhillite, cerussite, malachite and hemimorphite.