Dolomite << DOL uh myt >> is a mineral that serves as the chief source of magnesium obtained from the earth’s crust. It is fairly hard and brittle and consists of calcium carbonate and magnesium carbonate. Pure dolomite may appear white or yellow. Impurities, such as manganese or iron, may make dolomite pink, brown, or some other color. Dolomite and a mineral called calcite, which consists only of calcium carbonate, often look alike.
The term dolomite also refers to rock composed principally of dolomite. This rock also is called dolostone or dolomite rock. Dolostone may form when magnesium carbonate replaces part or all of the calcium carbonate in limestone or the skeletal remains of marine organisms. The rock also may form from minerals that settle out of seawater, or from hardened deposits of mud and mineral matter.
The Dolomite Mountains in northeastern Italy were named for the mineral in the late 1700’s. Many other mountain ranges in Europe and other parts of the world have great masses of dolomite rock. The rock also occurs in various parts of North America.
Iron and steel manufacturers use dolomite in the smelting process. Finely ground dolomite is used as a filler in paint, putty, and rubber. Marble composed of dolomite crystals is famous for its unusual colors and is used as a building material.
See also Marble.
