Natural Source of Calcium and Minerals We do not mix it together with other ingredients natural mineral block is a natural product that doesn't contain toxins or contaminants. An inexpensive and all-natural source of calcium carbonate and other trace minerals for your bird. And yes, it is 100% natural occurring limestone, so it will not come in any shapes Calcium & Minerals help birds with bone formation and blood clotting Iron aids with the red blood cell formation and function Potassium maintains normal heart and muscle activity Zinc helps with the immune system Copper assists with proper circulation and healing