Dolomite with Quartz and Malachite (rare) from the Auyda mine in Mistromen, Morocco

Dolomite or bitterspar is a carbonatic mineral; calcium-magnesium carbonate with the chemical formula CaMg(CO3)2. Rocks that largely consist of this mineral are also called dolomite, and the name dolostone is also used to distinguish them. Dolomite resembles calcite in appearance, but despite the basic carbonate ion it dissolves poorly or not at all in hydrochloric acid. It is not known exactly how the mineral is formed, one possibility is that it happens in shallow sea water in (sub) tropical areas, but other mechanisms are also possible. Although the rock is usually not formed by sedimentation, it is still considered a sedimentary rock. The mineral owes its name to the 18th-century French geologist Déodat de Dolomieu, who discovered this mineral in the mountain range that has since been called the Dolomites after him. The mineral usually occurs secondarily in limestone, where dolomite is formed by converting pure calcium carbonate. Because Mg ions occupy places occupied by Ca ions in the crystal lattice, holes are created in the rock on both an atomic and macro scale. This is typical of secondary dolomite. Dolomite is used as a natural stone, but also as a raw material for cement, as a source of magnesium oxide and for the production of refractory bricks.