Cal-Mag (Coral) Supplements Introduction to Coral Cal-Mag: Nature's Bone Health SolutionCoral is the skeletal structure of a marine animal, and also makes up coral reefs. Coral calcium is typically derived from fossilized coral and collected directly from coastal land or the waters that surround it. This form of calcium is composed primarily of calcium carbonate which has a high concentration of elemental calcium (40%), as well as, to a lesser extent, magnesium, and the full spectrum of trace elements. https://www.nationalnutrition.ca/calcium-magnesium/cal-mag-coral.html #CalciumMagnesiumSupplements