Calcium, a metallic element, is fifth in abundance in the earth's crust, of which it forms more than 3%. It is an essential constituent of leaves, bones, teeth, and shells. Never found in nature uncombined, it occurs abundantly as limestone, gypsum, and fluorite.

Can calcium be found naturally?

Natural abundance

Calcium is the fifth most abundant metal in the Earth's crust (4.1%). It is not found uncombined in nature, but occurs abundantly as limestone (calcium carbonate), gypsum (calcium sulfate), fluorite (calcium fluoride) and apatite (calcium chloro- or fluoro-phosphate).

Where is calcium most commonly found in food?

In food, calcium is found in mineral form. Foods high in calcium include dairy products — such as milk, cheese and yogurt — and some vegetables, such as kale, watercress, spinach and broccoli. In order for calcium to absorb properly, it should be taken with vitamin D.