Element collecting from hydrogen to bismuth (except the radioactive technetium and promethium) are collected, with the exceptions of the extremely long-lived thorium and uranium. It is possible to source other radioactive elements, such as radium (usually in the form of radium sulphate as part of luminescent paint on antique watch hands), tritium - a radioactive isotope of hydrogen, americium (in the form of radioactive buttons containing 0.29 micrograms of americium extracted from older smoke detectors), and technetium. Element collecting Element collecting is the hobby of collecting the chemical elements. Many element collectors simply enjoy finding peculiar uses of chemical elements. Others enjoy
Uranium–uranium dating between the ranges of Th/U (accurate up to ca. 450,000 years) and U–Pb dating (accurate up to the age of the solar system, but problematic on samples younger than about 2 million years). Uranium–uranium dating Uranium–uranium dating is a radiometric dating technique which compares two isotopes of uranium (U) in a sample: uranium-234 (U) and uranium-238 (U). It is one of several radiometric dating techniques exploiting the uranium radioactive decay series, in which U undergoes 14 alpha and beta decay events on the way to the stable isotope Pb. Other dating techniques using this decay series include uranium–thorium dating and