Dolomite, a mineral made up of calcium and magnesium carbonate. It has a glassy or pearly appearance and is most often white or pink, but can also be red, brown, or gray. Dolomite is a common mineral and is found throughout the world, chiefly as veins and strata (layers) in limestone, marble, and ores of metals such as lead and zinc. Limestone with a high percentage of dolomite is known as dolomite limestone; marble rich in dolomite is sometimes called dolomitic marble. In both mineral and rock form, dolomite is especially abundant in the Dolomite Alps of northern Italy and in the midwestern United States.

Dolomite limestone is used as a building and ornamental stone, in the manufacture of cement, and as a source of magnesium.

Chemical formula: CaMg(CO3)2, Specific gravity: 2.8-2.9. Hardness: 3.5-4.0. Crystalline form: Hexagonal.