For artworks, it may be sufficient to confirm whether a piece is broadly ancient or modern (that is, authentic or a fake), and this may be possible even if a precise date cannot be estimated.
Natural crystalline materials contain imperfections: impurity ions, stress dislocations, and other phenomena that disturb the regularity of the electric field that holds the atoms in the crystalline lattice together.
Therefore, at that point the thermoluminescence signal is zero.
An example of this can be seen in Rink and Bartoll, 2005.
As a crystalline material is heated during measurements, the process of thermoluminescence starts.
Thermoluminescence emits a weak light signal that is proportional to the radiation dose absorbed by the material. The technique has wide application, and is relatively cheap at some US0–700 per object; ideally a number of samples are tested. The destruction of a relatively significant amount of sample material is necessary, which can be a limitation in the case of artworks.
The heating must have taken the object above 500° C, which covers most ceramics, although very high-fired porcelain creates other difficulties.
It will often work well with stones that have been heated by fire.
In order to relate the signal (the thermoluminescence—light produced when the material is heated) to the radiation dose that caused it, it is necessary to calibrate the material with known doses of radiation since the density of traps is highly variable.