1. what is difference between calcite, calcium carbonate, limestone?
Calcite is rhombical shape transparent crystal which is rare in occurance. It is very costly because of underground vein mining inside the earth. Its price varies around 3 to 5 rs per kg of raw material. Mainly used in pharma.
Calcium carbonate is CaCO3. It is not a powder or a product. It is a chemical composition. Anything which contains CaCO3 can be called as calcium carbonate powder. Calcite, Limestone, Aragonite, even Marble etc. can be termed as Calcium Carbonate or CaCO3 powder.