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 ore precipitation of uranium minerals in form of coffinite, pitchblende and U-Zr-silicates. This initial mineralisation event took place at about 277 million to 264 million years. During the Triassic a further mineralisation event took place relocating uranium into quartz-carbonate-uranium veins. Another example of this mineralisation style is the Shinkolobwe deposit in Congo, Africa, containing about 30,000 t of uranium. Intrusive deposits make up a large proportion of the world's uranium resources. Included in this type are those associated with intrusive rocks including alaskite, granite, pegmatite and monzonites. Major world deposits include Rossing (Namibia), Ilimaussaq intrusive complex (Greenland) and Palabora (South Africa).