Magnesium carbonate 500gm, MgCO₃, is a colorless or white solid. Several hydrated and basic forms of magnesium carbonate exist as minerals. This is the laboratory-grade reagent. The primary use of magnesium carbonate is the production of magnesium oxide by calcining. Magnesite and dolomite minerals are used to produce refractory bricks. MgCO3 is also used in flooring, fireproofing, fire extinguishing compositions, cosmetics, dusting powder, and toothpaste. Magnesium carbonate 500gm is an antacid for symptomatic relief of heartburn, indigestion, and upset stomach. Magnesium carbonate, or magnesite, is a common over-the-counter remedy for heartburn and upset stomach caused by the overproduction of acid in the stomach.