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
Uranium tile still standing from that era by use of a simple geiger counter that readily detects the beta radiation emitted by uranium's ever-present decay chain radio-daughters. In most situations, the radiation exposure is not excessive, but there are some exceptions in which pure uranium oxide [which produces red-orange coloration as a glaze] on bathroom floors can pose a hazard for infants crawling around for hours on end, day after day. ORAU Radioactive Tiles Uranium tile Uranium tiles have been used in the ceramics industry for many centuries, as uranium oxide makes an excellent ceramic glaze, and is reasonably abundant on the