composition of talc usually stays close to this generalized formula, some substitution occurs. Small amounts of Al or Ti can substitute for Si; small amounts of Fe, Mn and Al can substitute for Mg; and, very small amounts of Ca can substitute for Mg.
Barite is a mineral composed of barium sulfate (BaSO4). It receives its name from the Greek word "barys" which means "heavy." This name is in response to barite's high specific gravity of 4.5, which is exceptional for a nonmetallic mineral.
Calcium carbonate, or CaCO3, comprises more than 4% of the earth’s crust and is found throughout the world. Calcium carbonate is one of the most useful and versatile materials known to man.