Strontium sulfide is the inorganic compound with the formula SrS. It is a white solid. The compound is an intermediate in the conversion of strontium sulfate, the main strontium ore called celestite, to other more useful compounds. Strontium sulfide is the inorganic compound with the formula SrS. It is a white solid. The compound is an intermediate in the conversion of strontium sulfate, the main strontium ore called celestite, to other more useful compounds. Strontium sulfide is produced by roasting celesite with coke at 110–1300 °C. The sulfate is reduced, leaving the sulfide: About 300,000 tons are processed in this way annually. Both luminous and nonluminous sulfide phases are known, impurities, defects, and dopants being important.