Chalcanthite
Image: Марися Лебідь (CC BY-SA 4.0)
Mineral NameChalcanthite
Chemical FormulaCuSO₄·5H₂O
Mohs Hardness2.5
Crystal Systemtriclinic
Lustervitreous
Streak Colorwhite
Cleavageimperfect on {110}
Fractureconchoidal
Specific Gravity2.2
Colorsblue, sky-blue, azure
Transparencytransparent
Type LocalityChuquicamata, Chile
Mineral GroupSulfates
Usescollector, minor copper ore, chemical industry (synthetic)
Associated Mineralsmalachite, azurite, brochantite, gypsum, limonite
Rarityuncommon
Description
This sample displays an intricate, branching growth of vibrant sky-blue crystals, characteristic of chalcanthite. The individual crystals are small and prismatic, forming a delicate, sparkling aggregate.
Geological Context
Chalcanthite is a secondary mineral that forms in the oxidized zones of copper sulfide deposits, particularly in arid environments where it is less prone to dissolution. It is a product of the weathering of primary copper minerals like chalcopyrite.
