Copper sulphate is a blue crystalline solid that is highly soluble in water, with a solubility of approximately 31.6% at 20 °C. It has a boiling point of 650 °C (decomposes) and a melting point of 110 °C (pentahydrate). Copper sulphate is manufactured through processes that involve the reaction of copper with sulphuric acid or the dissolution of copper oxide in diluted sulphuric acid. In the first method, metallic copper reacts with concentrated sulphuric acid, often with heat, to produce copper sulphate and water. Alternatively, copper oxide can be dissolved in diluted sulphuric acid to yield copper sulphate. The copper sulphate pentahydrate is then recovered by cooling the solution, allowing the compound to crystallize into its characteristic blue crystalline form.