Calcium ion (Ca²⁺) is a positively charged ion formed when a calcium atom loses two electrons. It plays a crucial role in various biological processes, including muscle contraction, nerve transmission, and blood clotting. Calcium ions are essential for maintaining healthy bones and teeth, as they contribute to the structure and strength of calcium phosphate in these tissues. In addition to its biological importance, Ca²⁺ is also significant in industrial applications. It is used in the production of cement, glass, and various chemical processes. Calcium ions are commonly found in nature, particularly in limestone and gypsum, which are important sources of calcium compounds.