Ca²+, or calcium ion, 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 is essential for maintaining strong bones and teeth, as it is a primary component of their structure. In addition to its biological importance, Ca²+ is also significant in industrial applications. It is used in the production of cement and glass, and it serves as a key ingredient in fertilizers. The presence of calcium ions in water can affect its hardness, influencing both environmental and health aspects.