Strontium occurs in nature in the form of the minerals celestite, strontianite, and brewsterite. Of these minerals, celestite, the strontium sulfate, is by far the most common and is for that reason the principal strontium ore. Strontianite, the strontium carbonate, is more valuable as an ore because of the ease with which it can be converted into the various strontium compounds of industrial usage but is rarely found in quantities large enough to have commercial importance. Brewsterite, or strontium silicate, is comparatively rare and has no present economic importance.

Strontium metal has at present no economic application, but strontium compounds are employed in a variety of uses. Their most characteristic property is the ability to impart a brilliant red color to flames. Because of this ability to produce a highly visible and distinctive flame, strontium salts are employed in the manufacture of fireworks, in fuses and signal flares for both civil and military uses, and in tracer bullets. In addition to the uses in pyrotechnics, strontium compounds are employed in gas refrigeration, in the process of refining caustic soda for the rayon industry, in the steel industry as a flux and scavenger agent in the manufacture of certain open-hearth steels, in paints as pigment, in rubber and plastics as a filler, and in chemicals and medicines. Recently, some Texas celestite has been utilized as an admix in drilling muds where it serves principally as a weighting agent to counteract high gas pressures. The specific gravity of celestite is 3.9.