Strontium is a metallic element, number 38 in the periodic table with the symbol Sr. An alkaline earth metal, strontium is a soft silver-white or yellowish material that is highly reactive chemically. It occurs naturally in the minerals celestine and strontianite. As a pure metal, strontium is used in aluminum alloys. The primary use for strontium compounds is in the faceplate glass for color television picture tubes to prevent X-ray emission. It is also used in pyrotechnics and ferrite ceramic magnets. China is reported the world’s largest producer.