All naturally occurring uranium contains 238U and 235U (in the ratio 137.7:1). Both isotopes are the starting points for complex decay series that eventually produce stable isotopes of lead. U decays to 206Pb (half-life = 4510 Ma, see decay constant) by a process of eight alpha-decay steps and six beta-decay steps.

Does uranium make lead?

Lead atoms created by uranium decay are trapped in the crystal and build up in concentration with time. If nothing disturbs the grain to release any of this radiogenic lead, dating it is straightforward in concept.

How does uranium look like?

When refined, uranium is a silvery white, weakly radioactive metal. When finely divided, it can react with cold water; in air, uranium metal becomes coated with a dark layer of uranium oxide. Uranium in ores is extracted chemically and converted into uranium dioxide or other chemical forms usable in industry.

How long does it take for 50 of U-238 to decay to Pb 206?

about 4.5 billion years After conducting careful measurements on large numbers of U-235 atoms, scientists determined that each U-238 atom has a 50% chance of decaying into Pb-206 during about 4.5 billion years. In other words, the half-life of U-238 is 14 billion years. Why does decay occur?

Where is the largest uranium deposit in the world?

McArthur River mine located about 620km north of Saskatoon, Canada, is currently the worlds largest uranium producing mine. It produced 7,520 tonnes of uranium in 2012, accounting for 13% of the worlds total uranium production.