Strontium sulfate may be precipitated from a solution of a soluble strontium salt, such as strontium nitrate or chloride, and a sulfate. Magnesium and potassium sulfate are both cheaply available as fertilizer and are convenient to use. The precipitated strontium sulfate is a very fine powder which may be rinsed by repeated washings with hot water, settling and decanting. A final washing in the filter with acetone or ethanol will allow it to dry quickly. Do not use sulfuric acid to precipitate strontium sulfate as this may result in the inclusion of acid droplets in the precipitated particles which can lead to spontaneous ignition of some mixtures.