Marine Coral Calcium is an excellent source of Calcium, magnesium, and trace minerals. Coral calcium contains up to 74 different minerals that are difficult to find in other sources of nutrition. The reason why is that the top soil that our fruits and vegetables are grown in are mineral deficient. Coral calcium is about the same price as other forms of calcium like calcium citrate. Mined from below sea (Marine) coral from Okinawa Japan. Finely ground to micron size particles for easy absorption.