Radium is nearly pure white. When it is exposed to air, though,
it immediately oxidizes, turning black. The heaviest of the
alkaline earth metals, radium is a chemical element whose atoms -
like those of the other alkaline earth metals - have two electrons
in their outermost shell; this causes them to react readily and
form numerous compounds. The luminescent quality in radium made it
ideal for use in self-luminous paints for watches, instrument
dials, clocks and the like. Unaware of the danger of the extreme
radioactivity of the element, many watch-dial painters who shaped
their paintbrushes by putting them between their lips, died from
the extended exposure to the radium in the paint. With its hazards
come benefits. Today, radium is used medically to treat some kinds
of cancer. On this date in 1898, scientists Pierre and Marie Curie
and Gustave Bemont discovered radium in pitchblende that came from
the now Czech Republic.
Radium has probably a silvery metallic appearance.