What is the most rare substance on earth?

Answer by  Sharyq1 (63)

The rarest substance found on earth must be the halogen Astatine. It is highly radioactive and unstable and decays into Lead as a final product. It behaves like a normal halogen like Iodine but is considered more metallic than the other halogens.

Answer by  ramoskenneth285 (631)

The element Astatine is the most rare substance on earth.It only exist in a very short period in the radio active decay chains of Plutonium,Uranium and Californium.Another element that could be the most rare substance in earth is Francium.They believe that 30 grams of Francium are estimated to exist in the earth everyday.