Calcium Carbonate A white colored rock, what specific gravity of 2.5 to 3, and a refractive index of 166, the micronized powder of whichis widely used owing toits low price and high capabilities as a filler substance in paint rubber plastic paper, PV. Cgranule, cable, adhesive, artificial leather,cosmetics, health and pharmaceutical industries. Calcium Carbonate contains 5% CaO and 44%CO2, which reacts rapidly withe acids. Due to minimum oil absorption as well as due to its easy permeability in the resins, this substance is widely used in paint manufacture and through the control of brightness and viscosity adjustment paint could be prevented from becoming mildewed.