1. The pure mineral dolomite has the composition CaMg(CO3)2 and has properties very similar to those of calcite. The rock dolomite consists mainly of the mineral dolomite, with subordinate calcite, and has properties very similar to those of limestone. The natural dissolution of dolomite is generally slower than that of limestone. Hence, dolomite karst is generally less well developed than limestone karst, though exceptions do occur in areas such as north-west Canada. Large, deep caves can form in dolomite, as in the Rand of South Africa . 2. A mineral composed of calcium magnesium carbonate, CaMg(CO3)2. 2. Rock chiefly composed of the mineral dolomite . Also called dolostone.