The mineral dolomite crystallizes in the trigonal-rhombohedral system. It forms white, gray to pink, commonly curved (saddle shape) crystals, although it is usually massive.

 Unlike calcite, dolomite is a double carbonate, having a different structural arrangement, and it does not rapidly dissolve or effervesce (fizz) in dilute hydrochloric acid unless it is scratched or in powdered form. Crystal twinning is common.

 A solid solution series exists between dolomite and iron rich ankerite. Small amounts of iron in the structure give the crystals a yellow to brown tint. Manganese substitutes in the structure also up to about three percent MnO.

 A high manganese content gives the crystals a rosy pink color noted in the image above. A series with the manganese rich kutnohorite may exist. Lead and zinc also substitute in the structure for magnesium. It is also related to huntite Mg3Ca(CO3)4.

 

Dolomite with chalcopyrite from the Tri-state district, Cherokee County, Kansas (size: 11.4×7.2×4.6 cm).

Dolomite is used as an ornamental stone, a concrete aggregate, a source of magnesium oxide and in the Pidgeon process for the production of magnesium.

It is an important petroleum reservoir rock, and serves as the host rock for large strata-bound Mississippi Valley-Type (MVT) ore deposits of base metals such as lead, zinc, and copper.

Where calcite limestone is uncommon or too costly, dolomite is sometimes used in its place as a flux for the smelting of iron and steel. Large quantities of processed dolomite are used in the production of float glass.

Home and container gardening are common examples of this use.Dolomite is also used as the substrate in marine (saltwater) aquariums to help buffer changes in pH of the water.

Particle physics researchers prefer to build particle detectors under layers of dolomite to enable the detectors to detect the highest possible number of exotic particles.

Because dolomite contains relatively minor quantities of radioactive materials, it can insulate against interference from cosmic rays without adding to background radiation levels.