Dolomite is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally CaMg(CO3)2. The term is also used for a sedimentary carbonate rock composed mostly of the mineral dolomite (see Dolomite (rock)). An alternative name sometimes used for the dolomitic rock type is dolostone.
Dolomite (white) on talc
Dolomite and calcite look similar under a microscope, but thin sections can be etched and stained in order to identify the minerals. Photomicrograph of a thin section in cross and plane polarised light: the brighter mineral grains in the picture are dolomite, and the darker grains are calcite.
Cristallo in the Dolomites mountain range near Cortina d'Ampezzo, Italy. The Dolomite Mountains were named after the mineral.
Carbonate minerals are those minerals containing the carbonate ion, CO2−3.
Calcite crystals from the Sweetwater Mine, Viburnum Trend District, Reynolds County, Missouri; 6.2 × 6 × 3.3 cm
Rhodochrosite, Sweet Home Mine, Alma, Colorado; 5.2 × 4.2 × 2.3 cm
Smithsonite, Silver Bill Mine, Dragoon Mts, Cochise County, Arizona; 4.8 × 4.1 × 2.4 cm
Dolomite with calcite and chalcopyrite from the Picher Field, Tri-State district, Cherokee County, Kansas; 12.0 × 9.7 × 4.3 cm
