Californium costs $ 27 million per gram. Why is it needed? An element of californium is so expensive to produce, the isotopes of californium do not have any practical application. In the West it was created only once since its opening in 1950. The californium is a ' chemical element with the symbol Cf and the atomic number 98. It is a transuranic element, synthetic , radioactive : californium has very few practical uses and was discovered by bombarding curium with alpha particles ( ions of helium ). The amount of synthesized californium, although small, have made it possible to evaluate some characteristics. The 252 Cf ( half-life 2.6 years) is a strong emitter of neutrons and it is therefore extremely radioactive and harmful (a microgram spontaneously emits 170 million neutrons per minute). The half-life of 254 Cf (55 days) can be detected by telescopes on remnants of supernovae . The249 Cf is formed by beta decay of 249 Bk and most other isotopes of californium are produced by bombarding the Berkelim with intense beams of neutrons in a nuclear reactor . This element has some very specialized applications that take advantage of its radioactivity, apart from these, it is too difficult to produce because it can have a significant use as a material.