Aragonite is a carbonate mineral and one of the three most common naturally occurring crystal forms of calcium carbonate, the others being calcite and vaterite. It is formed by biological and physical processes, including precipitation from marine and freshwater environments.
Aragonite from Los Molinillos, Cuenca, Spain, sample width about 4 cm
Aragonite crystals from Cuenca, Castile-La Mancha, Spain
Aragonite crystal cluster from Spain
Remnant biogenic aragonite (thin, rainbow-colored shell) on the ammonite Baculites (Pierre Shale, Late Cretaceous, South Dakota)
Carbonate minerals are those minerals containing the carbonate ion, CO2−3.
Calcite crystals from the Sweetwater Mine, Viburnum Trend District, Reynolds County, Missouri; 6.2 × 6 × 3.3 cm
Rhodochrosite, Sweet Home Mine, Alma, Colorado; 5.2 × 4.2 × 2.3 cm
Smithsonite, Silver Bill Mine, Dragoon Mts, Cochise County, Arizona; 4.8 × 4.1 × 2.4 cm
Dolomite with calcite and chalcopyrite from the Picher Field, Tri-State district, Cherokee County, Kansas; 12.0 × 9.7 × 4.3 cm