is limestone high in calcium
â¢ High-Calcium Limestone: â¢ Magnesian Limestone: Lastly, some dolomites contain an excess of magnesium (Mg) and are called magnesian dolomite or high-magnesium dolomite. The excess magnesium is probably in the form of magnesium carbonate minerals, of which magnesite (MgCO3) is a possible candidate. It is used as a soil conditioner to neutralize acidity and to add calcium and magnesium nutrients. 2  Quicklime is calcium oxide (formula CaO) that is produced by calcining (burning) high-calcium limestone in a lime kiln to drive out the carbon in the form of carbon dioxide gas (formula CO2).