Barium

Barium is a soft, silvery metal that reacts quickly with air and water, so it is used almost entirely as compounds. Its name comes from the Greek for heavy, after its dense main ore, barite. Most barite is ground up and added to drilling mud to keep oil and gas wells under control.

In the television, barium starts as barium carbonate, which is heated with titanium dioxide to make barium titanate, the ceramic inside every multilayer ceramic capacitor. Barium sulfate blocks X-rays yet passes through the body harmlessly, so patients swallow it before X-rays of the gut. Barium salts also give fireworks their green color.