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As the mineral cools, the crystal structure begins to form and diffusion of isotopes is less easy.

The temperature at which this happens is known as the closure temperature or blocking temperature and is specific to a particular material and isotopic system.

These temperatures are experimentally determined in the lab by artificially resetting sample minerals using a high-temperature furnace.

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.

All ordinary matter is made up of combinations of chemical elements, each with its own atomic number, indicating the number of protons in the atomic nucleus.

Additionally, elements may exist in different isotopes, with each isotope of an element differing in the number of neutrons in the nucleus.

Finally, correlation between different isotopic dating methods may be required to confirm the age of a sample.

For example, the age of the Amitsoq gneisses from western Greenland was determined to be Accurate radiometric dating generally requires that the parent has a long enough half-life that it will be present in significant amounts at the time of measurement (except as described below under "Dating with short-lived extinct radionuclides"), the half-life of the parent is accurately known, and enough of the daughter product is produced to be accurately measured and distinguished from the initial amount of the daughter present in the material.

This predictability allows the relative abundances of related nuclides to be used as a clock to measure the time from the incorporation of the original nuclides into a material to the present.

The basic equation of radiometric dating requires that neither the parent nuclide nor the daughter product can enter or leave the material after its formation.

Another possibility is spontaneous fission into two or more nuclides.