Calcite is a common mineral made of calcium carbonate (CaCO₃). It is found in various geological environments, including sedimentary rocks like limestone and marble. Calcite can appear in many colors, including clear, white, yellow, and blue, and it often forms in crystal shapes, such as rhombohedra. Calcite is important in various industries, including construction and agriculture. It is used to produce cement and lime, which are essential for building materials. Additionally, calcite plays a role in soil conditioning and is a key component in the formation of stalactites and stalagmites in caves.