December 26

On 26 December 1898, physicists and chemists Marie and Pierre Curie announced in Paris the existence of a new element they named "radium" for its intense radioactivity – a word they coined. The element (symbol Ra) is an almost pure-white earth metal that luminesces a faint blue color because of its instability. Before radioactivity’s adverse health effects were understood, radium was added to products such as toothpaste, hair creams and even food items for its supposed “curative” powers. It also was used in self-luminous paints for watch dials, clocks and other instruments. "Radium Girl" dial-painters using the paints became ill with anemia, sores and bone cancer. Marie Curie’s papers from the 1890s are still considered too dangerous to handle; they are kept in lead-lined boxes, and researchers must wear protective clothing. Even her cookbook is highly radioactive.