The difference between chemical limestone and dolomite is that dolomite has a magnesium and limestone has calcium
Limestone is composed of calcite or calcium carbonate, CaCO3, and dolostone is composed of dolomite or calcium magnesium carbonate, Ca,Mg(CO3). Okla gave the chemical formula for ankerite, which is in the dolomite group. In the field dolostone and limestone are difficult to tell apart (but there crystals are fairly diagnostic).one way is to drop some HCl on them. Limestone will fizz (effervesce) and dolostone will not.UNLESS it is powdered.then it will fizz.
