The dating method is usually performed on the mineral zircon.
The mineral incorporates uranium and thorium atoms into its crystal structure, but strongly rejects lead.
The method works best if neither the parent nuclide nor the daughter product enters or leaves the material after its formation.
Anything which changes the relative amounts of the two isotopes (original and daughter) must be noted, and avoided if possible.
Finally, ages can also be determined from the U–Pb system by analysis of Pb isotope ratios alone. Clair Cameron Patterson, an American geochemist who pioneered studies of uranium–lead radiometric dating methods, is famous for having used it to obtain one of the earliest estimates of the age of the Earth.
Although zircon (Zr Si O) is most commonly used, other minerals such as monazite (see: monazite geochronology), titanite, and baddeleyite can also be used.
Radiometric dating methods are used to establish the geological time scale.
These types of minerals often produce lower precision ages than igneous and metamorphic minerals traditionally used for age dating, but are more common in the geologic record.
During the alpha decay steps, the zircon crystal experiences radiation damage, associated with each alpha decay.
Zircon crystals with prolonged and complex histories can thus contain zones of dramatically different ages (usually, with the oldest and youngest zones forming the core and rim, respectively, of the crystal), and thus are said to demonstrate inherited characteristics.
Unraveling such complications (which, depending on their maximum lead-retention temperature, can also exist within other minerals) generally requires in situ micro-beam analysis via, say, ion microprobe (SIMS) or laser ICP-MS.