Dolomite, a trigonal carbonate mineral, has the chemical formula CaMg(CO3)2. It sometimes contains isomorphous elements such as iron and manganese, which substitute for magnesium. When the number of iron or manganese atoms exceeds that of magnesium, it is called iron dolomite or manganese dolomite.
Dolomite crystals are rhombohedral, with crystal faces often curved into a saddle shape; polysynthetic twinning is also common. Its aggregates are usually granular. Pure dolomite is white, gray when containing iron, and brown after weathering. It has a vitreous luster and is the main mineral component of dolomite.
Marine sedimentary dolomite often occurs interbedded with siderite and limestone layers. In lacustrine sediments, dolomite is associated with gypsum, anhydrite, halite, and potassium halite.
These characteristics of dolomite give it an important place in the fields of geology and mineralogy. Understanding dolomite is like opening a door to the geological world.
