Any member of a family of minerals that contains the carbonate ion, CO 3 2- , as the basic structural unit.
The carbonates are among the most widely distributed minerals in the earth's crust ; the most common are calcite , dolomite , and aragonite . Dolomite replaces calcite in limestones; when this replacement is extensive, the rock is called dolomite. Other relatively common carbonate minerals are siderite , rhodochrosite , strontianite (strontium-rich); smithsonite (zinc-rich); witherite (barium-rich); and cerussite (lead-rich).