Radium

Radium is a chemical element with symbol Ra and atomic number 88. Radium is an almost pure-white alkaline earth metal, but it readily oxidizes on exposure to air, becoming black in colour. All isotopes of radium are highly radioactive, with the most stable isotope being radium-226, which has a half-life of 1601 years and decays into radon gas. Because of such instability, radium is luminescent, glowing a faint blue

Radium, in the form of radium chloride, was discovered by Marie Curie and Pierre Curie in 1898. They extracted the radium compound from uraninite and published the discovery at the French Academy of Sciences five days later. Radium was isolated in its metallic state by Marie Curie and André-Louis Debierne through the electrolysis of radium chloride in 1910. Since its discovery, it has given names like radium A and radium C2 to several isotopes of other elements that are decay products of radium-226.

Radium is not very interesting to biologists because it is not necessary for life. It is, in fact, quite harmful to life due to its radioactivity and chemical reactivity. However, this did not stop a 30-year radium craze in the United States, where some people and manufacturers claimed radium to be a "wonder drug" and added it to all sorts of items, from toothpastes and suppositories to foods and even to drinking water, claiming it prevented or cured all sorts of ailments, ranging from arthritis and cancer to mental illness.  Yet at the same time that radium's health effects were being touted, it was also being added to pesticides and insecticides.

Radium is luminescent, glowing a lovely pale blue colour. This quality led to it being incorporated into a paint for watch and clock hands and dials in the United States, causing the deaths of many dial painters (all young women) who used their lips to give their paint brushes a fine point. These women, dubbed "Radium Girls", ended up suffering from a number of health problems such as anemia and cancer. Some Radium Girls ingested so much radium that their hair, hands, faces and arms glowed a luminous pale blue in the dark.

Radium covered watch hands under UV light

It wasn't as though there wasn't adequate warning of radium's dangers; its discoverer, Nobel-laureate Marie Curie, noted that a vial containing radium that she carried in her pocket caused an ulcer to appear on her skin. She later died of aplastic anaemia, most likely due to her years of exposure to radiation.