Crystallization is a process where a solid forms from a liquid or gas, creating a structured arrangement of atoms or molecules. This occurs when the concentration of a solute exceeds its solubility, leading to the formation of crystals. Common examples include the formation of salt from seawater or sugar from a sugar solution. In nature, crystallization can be observed in the formation of minerals within rocks or the growth of ice crystals in freezing conditions. This process is essential in various industries, including pharmaceuticals, where it helps purify compounds and create specific solid forms of drugs.