Magnesium carbonate is an odorless white powder with several industrial uses. It occurs in nature or as a manufactured substance.
The chemical formula for magnesium carbonate is MgCO3. It is slightly alkaline, rather than acidic.
In nature, magnesium carbonate occurs in the minerals magnesite and dolomite and in most limestones. Adding carbon dioxide to magnesium compounds produces manufactured magnesium carbonate.
Manufacturers use magnesium carbonate to insulate boilers and pipes against heat and in drugs, including antacids and laxatives. It is also an additive for food, makeup, glass, ink and rubber.
Magnesium carbonate does not dissolve in water, but will dissolve and effervesce in dilute acids.
The Morton Salt company added magnesium carbonate to its table salt in 1911 to keep the product from caking in wet conditions. The slogan, "When it rains, it pours," comes from that development.