Is your pet getting enough calcium and essential minerals? With Animal Essentials Natural Calcium, derived from a vegetable source, you can be sure of purity plus bio-availability! Animal Essentials calcium is a natural seaweed product harvested from the seabed off the southwest coast of Iceland. There amongst the cleanest and purest waters found anywhere in the world grows the small red seaweed Lithothamnium, which is composed of a wide variety of body essential nutrients including calcium, magnesium, boron, and zinc. The unique porosity of the particles makes this product much more bioavailable than bone meal or other calcium sources.