The leaden box and the gram of radium

It is through a national subscription among American women that the radium was offered to Marie Curie. May 21st, 1921, the US President, Warren G. Harding, symbolically handed to the scholar a golden key to the box, marked with the name of the White House. Marie Curie went to the Standard Chemical Company a few days later to receive the gram of radium. The leaden box in mahogany, with a weight of 46 kg, is made of two metals: one ornamental, engraved with inscriptions, the other lead, to limit radiation. This lead shielding is not thick enough to stop all the radiation from a gram of radium.

The gram of radium offered to Marie Curie in 1921 was used during her research in the laboratory and in the development of radiotherapy at the Curie Foundation by Doctor Regaud. The remains of the radium have since been disposed of as radioactive waste, following the ban on its use and possession in the 1970s. Therefore, the Musée Curie displays a copy of the tubes which contained the radium, such as they are described in the certificate which accompanied the gift.

Because of its rarity and high demand, radium had become the most expensive material in the world: in equal mass, it was worth more than diamond. One gram of radium costed $ 100,000 at the time (a bit less than 2 million euros in 2018). Worried of transmitting this precious material, Marie Curie decided, a few months before her death in 1934, to make a will on the future of this gram of radium after her death. She bequeathed it, by a signed document, to the University of Paris, under condition that her daughter Irène could continue to use it.