Kottigite from Ojuela Mine, Mapimí, Durango, Mexico

$650.00

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The top side of this matrix liberally scattered with prismatic crystals of the kottigite-parasymplesite group measuring to 1.3 cm in size. These are altering to an unknown mineral that is yellowish green. The specimen comes with a previous label from the collection of Ray DeMark. He acquired the piece in 1976. The Ojuela Mine, located in Mapimi, Durango, Mexico, was discovered by Spanish prospectors in 1598 and operated intermittently for over 350 years before closing commercially in 1932. Geologically, the deposit is hosted within deformed Cretaceous limestone units that have been intruded by Tertiary igneous rocks, creating an extensive hydrothermal pipe and vein system. Intense secondary oxidation processes acting on primary sulfide mineralization have produced a world-renowned zone of rich secondary mineral assemblages, making the mine famous for its exceptional variety of colorful arsenates, carbonates, and oxides. The kottigite-parasymplesite series represents a solid solution group of hydrated metal arsenates belonging to the vivianite group. Members of this series typically form as rare secondary minerals in the oxidized zones of arsenic-rich hydrothermal metal deposits. Within this crystal structure, divalent cations substitute for one another, bridging a compositional spectrum where zinc dominates one end and iron dominates the other. Crystals in this series often occur as prismatic formations, crusts, or radiating fibrous aggregates displaying colors that range from colorless and white to pale shades of pink, blue, or green depending on the specific metallic content.