Calcium is a metallic element that burns when introduced to oxygen to form calcium oxide. The red and white flame burns intensely, resulting in a white powder.
Calcium is an alkaline earth metal. It is soft and silvery-white in appearance. It is the fifth-most commonly found element in the Earth's crust, making up approximately 3 percent of the planet's oceans and soil. Calcium does not exist on its own in nature, but is found in compounds, including calcium carbonate (limestone), calcium sulfate (gypsum), and calcium fluoride (fluorite).
Calcium is a crucial component of a healthy body. It plays an important role in building strong bones and healthy muscles. Calcium is also essential in the transmission of nerve impulses to the nervous system. There is more calcium in the human body than any other mineral, and a constant supply is required to remain healthy. A lack of calcium increases the risk of diseases, such as osteoporosis, colon cancer and hypertension.
The average adult needs 1,000 to 1,200 milligrams of calcium per day. Foods that are rich in calcium include dairy products and leafy green vegetables, such as kale and spinach. Foods that are fortified with calcium, such as tofu, juices and soy milk, are also excellent sources.