Calcium magnesium carbonate, with the CAS number 19569-21-2, is a mineral compound also known as dolomite. It is a double carbonate of calcium and magnesium with the chemical formula CaMg(CO₃)₂. It is a naturally occurring mineral with a trigonal-rhombohedral crystal system and is the primary component of the sedimentary rock dolostone. Its primary industrial applications are as a functional filler and precursor material. In the materials sector, it is a key raw material for the production of magnesium metal, refractory bricks, and glass. As a functional powder, it is widely used as a filler and extender in plastics, paints, coatings, and rubber to improve mechanical properties and reduce costs. It also serves as a soil conditioner in agriculture to neutralize acidic soils and as a source of magnesium and calcium for plants. Other significant uses include serving as a flux in iron and steel production, a construction aggregate, and a source material for the synthesis of other magnesium compounds. Its properties, such as whiteness, thermal stability, and low cost, make it a versatile industrial mineral.