Chalcanthite is a blue, crystalline mineral composed of hydrated copper sulfate, with the chemical formula CuSO₄·5H₂O. It typically forms in arid environments through the evaporation of copper-rich solutions, often found in the oxidation zones of copper deposits. Its vibrant blue color and glassy luster make it visually striking. This mineral is soluble in water and can be toxic if ingested, as it releases copper ions. Chalcanthite is often studied in mineralogy and can be used in various applications, including as a source of copper in some industrial processes.