The BBC's Justin Rowlatt looks at the economics behind chemical elements.
The element that is behind lighting and writing.
The element that brought us beyond the Stone Age.
Calcium is a fundamental building block in chemistry and in modern life.
Carbon is the ultimate bonder but in some forms, it can be dangerous. Carbon Monoxide can poison you. Carbon Dioxide is blamed by some for global warming.
Aluminum or aluminium? Either way, it's useful.
Helium is a valuable finite resource that is often wasted just for fun.
