Aragonite is a mineral composed of calcium carbonate, with the chemical formula CaCO₃. It is one of the two primary crystal forms of calcium carbonate, the other being calcite. Aragonite typically forms in marine environments, often as a result of biological processes, such as the shells of mollusks and corals. This mineral is known for its needle-like crystal structure and can be found in various colors, including white, blue, and green. Aragonite is also significant in geology and paleontology, as it can provide insights into past environmental conditions and the history of marine life.