Most Expensive Materials On Earth By Weight (per gram)
2. Californium – $27 million per gram
Californium is a radioactive metallic chemical element with symbol Cf and atomic number 98. The element was first made in 1950 at the University of California Radiation Laboratory in Berkeley, by bombarding curium with alpha particles (helium-4 ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all the elements that have been produced in amounts large enough to see with the unaided eye (after einsteinium). The element was named after the university and the state of California. It is the heaviest element to occur naturally on Earth; heavier elements can only be produced by synthesis.
Discovered in California in 1950, Californium is a rare earth metal that doesn’t occur naturally on the planet. Highly radioactive, one microgram of Californium releases up to 170 million neutron particles every minute, making it extremely toxic to most organic life. Uses of this element include detection of gold, platinum and moisture gauges for oil wells.