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.
The mineral dolomite crystallizes in the trigonal-rhombohedral system. It forms white, tan, grey, or pink crystals. Dolomite is a double carbonate, having an alternating structural arrangement of calcium and magnesium ions.