Limestone, chalk, and marble are all naturally occurring sources of the white, soluble mineral calcium carbonate. It is a primary component of seashells, snail shells, and eggshells. In addition, our offering can be used to create marble, limestone, and chalk for blackboards. Calcium carbonate is used as a dietary supplement when the calcium intake from food alone is insufficient. For healthy bones, muscles, a neurological system, and a heart, the body needs calcium. It comes in various quantities in a perfectly sealed packaging.