Calcium strontium or barium, the oxide–nitride coating that results in air is stable and lathe machining and other standard metallurgical techniques are suitable for calcium. In the United States and Canada, calcium is instead produced by reducing lime with aluminium at high temperatures. Calcium provides a link between tectonics, climate, and the carbon cycle. In the simplest terms, uplift of mountains exposes calcium-bearing rocks to chemical weathering and releases Ca into surface water. These ions are transported to the ocean where they react with dissolved CO to form limestone (), which in turn settles to the sea floor where it is
Coral calcium Coral calcium Coral calcium is a salt of calcium derived from fossilized coral reefs (primarily from limestone and coastal deposits). It has been promoted as an alternative, but unsubstantiated, treatment or cure for a number of health conditions. Coral calcium has been promoted as an alternative treatment or cure for a number of health conditions, often as part of an alkaline diet, by Robert Barefoot and others; Barefoot coauthored a book called "The Calcium Factor," and marketed coral calcium supplements with infomercials. According to a "Time" magazine article about Barefoot by Leon Jaroff, "The monthly cost of the recommended dose