Dolomite /ˈdɒləmaɪt/ is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally CaMg(CO 3) 2. The word dolomite is also used to describe the sedimentary carbonate rock, which is composed predominantly of the mineral dolomite (also known as dolostone).ost probably the mineral dolomite was first described by Carl Linnaeus in 1768. In 1778, it was described by the Austrian naturalist Belsazar Hacquet as the stinking stone (German: Stinkstein, Latin: lapis suillus).