Strontium

Strontium is a soft, silvery metal similar to calcium. It is named after Strontian, a village in Scotland where its mineral was found in lead mines; Adair Crawford recognized it as something new in 1790. Today it is mined mostly as celestine, a strontium sulfate, in countries such as Spain, Mexico and China.

Strontium compounds burn with a brilliant crimson flame, giving fireworks and road flares their red. In the television, it becomes strontium oxide, a glass ingredient. That oxide was once added to the glass of tube televisions to block X-rays, and it still helps tune the properties of flat-panel display glass.