Radium of radium Curie used the residues after extraction of uranium from pitchblende. The uranium had been extracted by dissolution in sulfuric acid leaving radium sulfate, which is similar to barium sulfate but even less soluble in the residues. The residues also contained rather substantial amounts of barium sulfate which thus acted as a carrier for the radium sulfate. The first steps of the radium extraction process involved boiling with sodium hydroxide followed by hydrochloric acid treatment to remove as much as possible of other compounds. The remaining residue was then treated with sodium carbonate to convert the barium sulfate into
Radium bromide from such a large amount of material, it was difficult to find a large quantity of radium. This was the reason radium bromide became one of the most expensive materials on earth. It was desired by many all around the world and there was very little to go around. In 1921, it was stated in "Times" magazine that radium cost 17,000,000,000 Euros per ton compared to gold at 208,000 Euros and coal, as diamond, at 400,000,000 Euros. A common reason that radium was added into almost everything at the time, including water and toys, was that people saw radium as