Eco-Friendly Dietary SupplementCoral Calcium is an excellent source of calcium, the single most abundant mineral in our bodies. In additional to building healthy bones, calcium plays essential roles in muscle contractions, heartbeat, blood clotting, nerve transmission, and in converting signals from hormones in the blood into actions within cells. Source Natural Coral Calcium is eco-friendly: It is harvested from fossilized (dead) coral and is not harmful to living coral.