Berkelium

Berkelium is a silvery-white, radioactive metal in the actinide family. It does not occur naturally in lasting deposits: any berkelium formed when Earth was young has long since decayed. Scientists make it in nuclear reactors by exposing heavier elements to intense neutron radiation, then carefully separate the tiny amounts produced. Berkelium has no commercial use; it is studied in basic research. One isotope, berkelium-249, has helped scientists create heavier elements, including tennessine. This makes berkelium valuable to research despite being available only in minute quantities.