Radium seventh of a gram of radium. One kilogram of the Earth's crust contains about 900 picograms of radium, and one liter of sea water contains about 89 femtograms of radium. Radium was discovered by Marie Sklodowska-Curie and her husband Pierre Curie on 21 December 1898, in a uraninite (pitchblende) sample. While studying the mineral earlier, the Curies removed uranium from it and found that the remaining material was still radioactive. They separated out an element similar to bismuth from pitchblende in July 1898, that turned out to be polonium. They then separated out a radioactive mixture consisting mostly of two
Radium Girls was about a penny and a half per dial (). The brushes would lose shape after a few strokes, so the U.S. Radium supervisors encouraged their workers to point the brushes with their lips ("lip, dip, paint"), or use their tongues to keep them sharp. Because the true nature of the radium had been kept from them, the Radium Girls painted their nails, teeth, and faces for fun with the deadly paint produced at the factory. Many of the workers became sick; it is unknown how many died from exposure to radiation. Many of the women later began to suffer