What age to start dating
As the mineral cools, the crystal structure begins to form and diffusion of isotopes is less easy.
This normally involves isotope-ratio mass spectrometry. The precision of a dating method depends in part on the half-life of the radioactive isotope involved.For most radioactive nuclides, the half-life depends solely on nuclear properties and is essentially a constant.It is not affected by external factors such as temperature, pressure, chemical environment, or presence of a magnetic or electric field.Precision is enhanced if measurements are taken on multiple samples from different locations of the rock body.
Alternatively, if several different minerals can be dated from the same sample and are assumed to be formed by the same event and were in equilibrium with the reservoir when they formed, they should form an isochron. In uranium–lead dating, the concordia diagram is used which also decreases the problem of nuclide loss.In these cases, usually the half-life of interest in radiometric dating is the longest one in the chain, which is the rate-limiting factor in the ultimate transformation of the radioactive nuclide into its stable daughter.