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
United States Radium Corporation years, it opened facilities in Newark, Jersey City, and Orange. In August 1921, von Sochocky was forced from the presidency, and the company was renamed the United States Radium Corporation. In Orange, where radium was extracted from 1917 to 1926, the U.S. Radium facility processed half a ton of ore per day. The ore was obtained from "Undark mines" in Paradox Valley, Colorado and in Utah. A notable employee from 1921 to 1923 was Victor Francis Hess, who would later receive the Nobel Prize in Physics. The company's luminescent paint, marketed as Undark, was a mixture of radium and zinc