Aragonite is a carbonate mineral that is a naturally occuring crystal form of calcium carbonate CaCO3. The formation occurs from both physical and biological processes. Which includes the precipitation from the freshwater and sea water environments.

Aragonite is a secondary formation has a different crystal lattice to calcite. Which is defined by its orthorhombic system with acicular crystals that is repeatedly twinned to result in pseudo-hexagonal forms. It may also be columnar or appear in stalactitic form.

This Crystal forms naturally in mollusk shells. Because the mineral deposition in these shells are strongly controlled biologically, they can differ in formation to inorganic Aragonite.