Most radioactive naturally occuring element

Polonium is generally considered to be the most radioactive element that is found naturally. Discovered in 1898 by Marie and Pierre Curie, polonium is found in uranium ores and has no stable isotopes among the 33 known to science. Its chemical symbol is Po, with an atomic number of 84, and it is generally considered to be a metalloid with both metallic and non-metallic properties. Samples of polonium are often seen to glow blue due to the intense radiation ionising gas particles around the sample. The rate of decay is such that a small sample of polonium will reach temperatures of around 500°C, and the outpouring radiation is enough to kill a human. The half-life of polonium is 138.39 days, hence it is a very rare element on Earth. While other man-made elements of higher atomic number could be considered more radioactive, they do not occur naturally and posses a half-life of between milliseconds and a few minutes, making polonium the accepted most radioactive element.