Gallium is the element that melts at about 30°C, so a piece can liquefy in a warm hand. Its melting point is approximately 29.76°C, just below normal human body temperature.
Gallium is a soft, silvery metal with atomic number 31. Dmitri Mendeleev predicted an undiscovered element with properties resembling gallium, calling it eka-aluminium; Paul-Émile Lecoq de Boisbaudran discovered gallium in 1875 and confirmed the prediction.
Gallium is often confused with mercury because both can be liquid near room temperature, but mercury remains liquid at ordinary room temperatures and gallium melts only when warmed. Gallium also expands when it freezes, a behavior shared by water and a few other substances.