All californium isotopes are radioactive. ... The isotope Cf-252 is a very strong neutron emitter, meaning it has the unusual property of giving off neutrons when it breaks apart. Isotopes that behave in this way are very unusual, according to Chemistry Explained.

What is californium known for?

Californium is a radioactive metal. Californium is a very strong neutron emitter. It is used in portable metal detectors, for identifying gold and silver ores, to identify water and oil layers in oil wells and to detect metal fatigue and stress in aeroplanes.

Which is the rarest element on the Earth?

A team of researchers using the ISOLDE nuclear-physics facility at CERN has measured for the first time the so-called electron affinity of the chemical element astatine, the rarest naturally occurring element on Earth.