- Calcium isn't found free in nature, but it can be purified into a soft silvery-white alkaline earth metal.
- Calcium is the 5th most abundant element in the Earth's crust, present at a level of about 3% in the oceans and soil.
- The element is essential for animal and plant nutrition. Calcium participates in many biochemical reactions, including building skeletal systems and moderating muscle action.
- While calcium and its compounds are not considered to be toxic, ingesting too many calcium carbonate dietary supplements or antacids can cause milk-alkali syndrome, which is associated with hypercalcemia sometimes leading to fatal renal failure. Excessive consumption would be on the order of 10 g calcium carbonate/day, though symptoms have been reported upon ingesting as little as 2.5 g calcium carbonate daily.
- Calcium is used for making cement, making cheese, removing nonmetallic impurities from alloys, and as a reduction agent in the preparation of other metals.
- Pure calcium metal reacts vigorously and sometimes violently with water and acids.
- The element name "calcium" comes from the Latin word "calcis" meaning "lime".
- Calcium has been known since the 1st century, when the ancient Romans were known to make lime from calcium oxide.
More About Calcium | Periodic Table & The Elements